[scheme mode] Recognize non-alphanumeric symbol chars
[scheme mode] Recognize non-alphanumeric symbol chars

And highlight non-builtin symbols as "variable".

Closes #537

karevn/CodeMirror,Carreau/CodeMirror,Dominator008/CodeMirror,skylarkcob/CodeMirror,belph/CodeMirror,rustemferreira/CodeMirror,adobe/CodeMirror2,SidPresse/CodeMirror,fmoliveira/CodeMirror,rustemferreira/CodeMirror,jpolitz/CodeMirror,melpon/CodeMirror,dperetti/CodeMirror,filonb/CodeMirror2,ZombieHippie/CodeMirror,isdampe/CodeMirror,bgrins/CodeMirror,ssxxue/CodeMirror,ejgallego/CodeMirror,Allenice/CodeMirror,sgoo/CodeMirror,ashmind/CodeMirror,michaelerobertsjr/CodeMirror,pabloferz/CodeMirror,flyskyko/CodeMirror,AlanWasTaken/codemirror,jayaprabhakar/CodeMirror,djadmin/CodeMirror,jayaprabhakar/CodeMirror,schanzer/CodeMirror,flyskyko/CodeMirror,Aliccer/CodeMirror,INTELOGIE/CodeMirror,kevinushey/CodeMirror,rustemferreira/CodeMirror,loopspace/CodeMirror,axter/CodeMirror,namin/CodeMirror,EasonYi/CodeMirror,Navaneethsen/CodeMirror,loopspace/CodeMirror,fivetran/CodeMirror,ssxxue/CodeMirror,buchslava/CodeMirror,manderson23/CodeMirror,nawroth/CodeMirror,rrandom/CodeMirror,elisee/CodeMirror,schanzer/CodeMirror,explorigin/CodeMirror,jessegrosjean/CodeMirror,amsul/CodeMirror,philuchansky/CodeMirror,ficristo/CodeMirror,increpare/CodeMirror,Carreau/CodeMirror,symbla/CodeMirror,kolya-ay/CodeMirror,skylarkcob/CodeMirror,Dominator008/CodeMirror,qiankun007/CodeMirror,nawroth/CodeMirror,dbarnett/CodeMirror,EasonYi/CodeMirror,Aliccer/CodeMirror,TDaglis/CodeMirror,CartoDB/CodeMirror,anthonygego/CodeMirror,pinbe/CodeMirror,kerabromsmu/CodeMirror,mihailik/CodeMirror,KamranMackey/CodeMirror,qweasd1/CodeMirror,karthikeyansam/CodeMirror,apatawari/CodeMirror,pabloferz/CodeMirror,kuangyeheng/CodeMirror,supriyantomaftuh/CodeMirror,gkoberger/CodeMirror,sourcelair/CodeMirror,anthonygego/CodeMirror,cintiamh/CodeMirror,hccampos/CodeMirror,MarcelGerber/CodeMirror,INTELOGIE/CodeMirror,GerHobbelt/CodeMirror2,mightyguava/CodeMirror,supriyantomaftuh/CodeMirror,vanloswang/CodeMirror,camellhf/CodeMirror,melpon/CodeMirror,pabloferz/CodeMirror,apatawari/CodeMirror,buchslava/CodeMirror,elisee/CodeMirror,michaelerobertsjr/CodeMirror,qweasd1/CodeMirror,xeronith/CodeMirror,kerabromsmu/CodeMirror,ssxxue/CodeMirror,grzegorzmazur/CodeMirror,gkoberger/CodeMirror,bluesh55/CodeMirror,abdelouahabb/CodeMirror,DustinH/CodeMirror,wingify/CodeMirror,xeronith/CodeMirror,sourcelair/CodeMirror,fpco/codemirror,pjkui/CodeMirror,increpare/CodeMirror,jhnesk/CodeMirror,adobe/CodeMirror2,d0liver/CodeMirror,dudb/CodeMirror,manderson23/CodeMirror,cintiamh/CodeMirror,vincentwoo/CodeMirror,INTELOGIE/CodeMirror,bgrins/CodeMirror,cintiamh/CodeMirror,wbinnssmith/CodeMirror,sekcheong/CodeMirror,skylarkcob/CodeMirror,kevinushey/CodeMirror,bfrohs/CodeMirror,thomasjm/CodeMirror,Jisuanke/CodeMirror,fmoliveira/CodeMirror,gkoberger/CodeMirror,hackmdio/CodeMirror,karevn/CodeMirror,ejgallego/CodeMirror,Icenium/CodeMirror,increpare/CodeMirror,AlanWasTaken/codemirror,kangkot/CodeMirror,webida/CodeMirror,matthewbauer/CodeMirror,dperetti/CodeMirror,sanyaade-iot/CodeMirror,ashmind/CodeMirror,sanyaade-iot/CodeMirror,symbla/CodeMirror,codio/CodeMirror,webida/CodeMirror,notepadqq/CodeMirror,morrisonwudi/CodeMirror,Navaneethsen/CodeMirror,pinbe/CodeMirror,Jisuanke/CodeMirror,amshali/CodeMirror,hccampos/CodeMirror,codio/CodeMirror,anthonygego/CodeMirror,crazy4chrissi/CodeMirror,manderson23/CodeMirror,symbla/CodeMirror,melpon/CodeMirror,amsul/CodeMirror,karthikeyansam/CodeMirror,amshali/CodeMirror,leoshine/CodeMirror,sekcheong/CodeMirror,kk9599/CodeMirror,namin/CodeMirror,karthikeyansam/CodeMirror,NeZaMy/CodeMirror2,jansel/CodeMirror,nawroth/CodeMirror,kk9599/CodeMirror,trumanliu/CodeMirror,KamranMackey/CodeMirror,KamranMackey/CodeMirror,pjkui/CodeMirror,nightwing/CodeMirror,ThebingServices/CodeMirror,filonb/CodeMirror2,matthewbauer/CodeMirror,happibum/CodeMirror-main,jkaplon/CodeMirror,mihailik/CodeMirror,sgoo/CodeMirror,joshterrell805-historic/CodeMirror,karevn/CodeMirror,pjkui/CodeMirror,jpolitz/CodeMirror,Icenium/CodeMirror,xeronith/CodeMirror,Ermlab/CodeMirror,grzegorzmazur/CodeMirror,alur/CodeMirror,InternetGuru/CodeMirror,ksanaforge/CodeMirror,angelozerr/CodeMirror,agendor/CodeMirror,shiren/CodeMirror,bocharsky-bw/CodeMirror,explorigin/CodeMirror,thomasjm/CodeMirror,cben/CodeMirror,NumbersInternational/CodeMirror,TechnicalPursuit/CodeMirror,joshterrell805-historic/CodeMirror,webida/CodeMirror,happibum/CodeMirror-main,dbarnett/CodeMirror,trumanliu/CodeMirror,crazy4chrissi/CodeMirror,qiankun007/CodeMirror,belph/CodeMirror,bfrohs/CodeMirror,leoshine/CodeMirror,sekcheong/CodeMirror,mtaran-google/CodeMirror,NeZaMy/CodeMirror2,axter/CodeMirror,djadmin/CodeMirror,Ermlab/CodeMirror,rasata/CodeMirror,dudb/CodeMirror,Jisuanke/CodeMirror,TDaglis/CodeMirror,amshali/CodeMirror,camellhf/CodeMirror,fpco/codemirror,nightwing/CodeMirror,r7kamura/CodeMirror,fivetran/CodeMirror,davidpham87/CodeMirror,hackmdio/CodeMirror,hccampos/CodeMirror,jochenberger/CodeMirror,adobe/CodeMirror2,ZombieHippie/CodeMirror,Icenium/CodeMirror,dperetti/CodeMirror,agendor/CodeMirror,SidPresse/CodeMirror,kuangyeheng/CodeMirror,ZombieHippie/CodeMirror,SidPresse/CodeMirror,AlanWasTaken/codemirror,dudb/CodeMirror,webida/CodeMirror,qweasd1/CodeMirror,kangkot/CodeMirror,notepadqq/CodeMirror,djadmin/CodeMirror,InternetGuru/CodeMirror,agendor/CodeMirror,rasata/CodeMirror,jessegrosjean/CodeMirror,ejgallego/CodeMirror,namin/CodeMirror,abdelouahabb/CodeMirror,isdampe/CodeMirror,camellhf/CodeMirror,Allenice/CodeMirror,philuchansky/CodeMirror,Navaneethsen/CodeMirror,jkaplon/CodeMirror,pinbe/CodeMirror,jkaplon/CodeMirror,InternetGuru/CodeMirror,d0liver/CodeMirror,philuchansky/CodeMirror,amireh/codemirror,buchslava/CodeMirror,NumbersInternational/CodeMirror,DustinH/CodeMirror,morrisonwudi/CodeMirror,kolya-ay/CodeMirror,bluesh55/CodeMirror,kk9599/CodeMirror,thomasjm/CodeMirror,DustinH/CodeMirror,bgrins/CodeMirror,wingify/CodeMirror,jessegrosjean/CodeMirror,grzegorzmazur/CodeMirror,crazy4chrissi/CodeMirror,ksanaforge/CodeMirror,ksanaforge/CodeMirror,CartoDB/CodeMirror,codio/CodeMirror,wbinnssmith/CodeMirror,jochenberger/CodeMirror,jayaprabhakar/CodeMirror,Aliccer/CodeMirror,belph/CodeMirror,antimatter15/CodeMirror,bocharsky-bw/CodeMirror,femhub/CodeMirror2,mizchi/CodeMirror,mtaran-google/CodeMirror,GerHobbelt/CodeMirror2,tpphu/CodeMirror,vanloswang/CodeMirror,mightyguava/CodeMirror,apatawari/CodeMirror,bfrohs/CodeMirror,dbarnett/CodeMirror,antimatter15/CodeMirror,nightwing/CodeMirror,angelozerr/CodeMirror,systay/CodeMirror,systay/CodeMirror,elisee/CodeMirror,Dominator008/CodeMirror,schanzer/CodeMirror,jhnesk/CodeMirror,vincentwoo/CodeMirror,TechnicalPursuit/CodeMirror,michaelerobertsjr/CodeMirror,Allenice/CodeMirror,ThebingServices/CodeMirror,bocharsky-bw/CodeMirror,shiren/CodeMirror,shiren/CodeMirror,bluesh55/CodeMirror,jansel/CodeMirror,MarcelGerber/CodeMirror,mihailik/CodeMirror,qiankun007/CodeMirror,supriyantomaftuh/CodeMirror,r7kamura/CodeMirror,mightyguava/CodeMirror,jpolitz/CodeMirror,ficristo/CodeMirror,d0liver/CodeMirror,femhub/CodeMirror2,loopspace/CodeMirror,trumanliu/CodeMirror,EasonYi/CodeMirror,filonb/CodeMirror2,ThebingServices/CodeMirror,davidpham87/CodeMirror,axter/CodeMirror,vincentwoo/CodeMirror,wingify/CodeMirror,antimatter15/CodeMirror,davidpham87/CodeMirror,rrandom/CodeMirror,fmoliveira/CodeMirror,flyskyko/CodeMirror,NumbersInternational/CodeMirror,notepadqq/CodeMirror,mtaran-google/CodeMirror,systay/CodeMirror,kerabromsmu/CodeMirror,kuangyeheng/CodeMirror,happibum/CodeMirror-main,isdampe/CodeMirror,tpphu/CodeMirror,matthewbauer/CodeMirror,MarcelGerber/CodeMirror,TechnicalPursuit/CodeMirror,mizchi/CodeMirror,alur/CodeMirror,r7kamura/CodeMirror,tpphu/CodeMirror,mizchi/CodeMirror,ficristo/CodeMirror,rasata/CodeMirror,rrandom/CodeMirror,NeZaMy/CodeMirror2,sanyaade-iot/CodeMirror,hackmdio/CodeMirror,femhub/CodeMirror2,alur/CodeMirror,cben/CodeMirror,vanloswang/CodeMirror,TDaglis/CodeMirror,sourcelair/CodeMirror,abdelouahabb/CodeMirror,morrisonwudi/CodeMirror,kangkot/CodeMirror,ashmind/CodeMirror