Added support for github gist embeds
Added support for github gist embeds

Fixes #26

Mr-Zer0/yansnote,malcolmocean/themindsui.theme,developer-prosenjit/Casper,fredeerock/atlab-ghost-theme,jasperla/ghost-Jasper,roikiermedia/Casper-modified,Zokormazo/Casper-eu,dlecina/StayPuft,eduardochiaro/Casper-Light,sawilde/Casper,BookingSync/SmilingCasper,molly/ghost-theme,jrummell/CasperJR,tandrewnichols/casper-dev,brnz/hboiled,tmack8001/skeletor-casper,emmmile/Casper,jrummell/CasperJR,bsansouci/Casper,zestyzesty/Casper,Flink/Casper,mnitchie/Casper,CAYdenberg/StayPuft,therecluse26/Establishment,jrfferreira/Casper,TheFynx/StayPuft-Dark,mistermark/Zeitgeist,diancloud/Casper,jtrussell/Jasper,krames/bbq-theme,abr4xas/Casper2Pelican,forfuturellc/Casper,tenoku/boo,emmmile/Casper,novaugust/Novasper,blade254353074/casper-custom,Inchdev/blog-theme,motatoes/casper-moe,happyfunboy/ghost_theme,ErisDS/Casper,vertigra/Ghostly,renattomachado/StayPuft,jedidja/Casper,dbulli/Duppy,Gaisuru/StayPuft,dolph/Casper,1cookco/Casper,Swaagie/neutral,hiroqli/Casper,matitalatina/Casper,lukaszklis/spooky,ErisDS/Casper,kdelfour/kd.eu-theme,Aaron1992/ak48,diogomonica/Casper,dolph/Casper,cobbspur/Rasper,Zokormazo/Casper-eu,AaronLenoir/Casper,yo1dog/Casper,michaelperrin/mike-ghost-theme,dlew/Casper,Samisdat/ghost-conway,makerdiary/Casper,schneidmaster/schneidseven,KlausTrainer/Casper,khsing/Haze,BookingSync/SmilingCasper,tiagojsalmeida/Kibosh-Ghost-Theme,diogomonica/Casper,Shaked/KzarimTheme,JDevlieghere/JCasper,chareice/clash,kaizvn/kMod-Casper,AaronLenoir/Casper,solobat/KCoder,alexshenoy/CasperModified,russmckendrick/Casper,DrZhi/Casper,Aplopio/ghost-theme,rizowski/Theme,DevL/Casper,jedidja/Casper,chin8628/Casper,fredeerock/atlab-ghost-theme,Mr-Zer0/yansnote,Larleyt/Casper,cjfuller/Casper,KlausTrainer/Casper,Rystakei/topdollar-theme,michaelperrin/mike-ghost-theme,realityone/RCasper,sshockwave/VSCodeTheme,dbulli/Duppy,realityone/RCasper,dpnl87/Ghosty,duyetdev/islab-theme,tomkwok/Casper,MoriTanosuke/kopis-ghost-theme,oddui/casper_littlehorse,Gimpneek/Casper2Pelican,alvareztech/Casper,ivanoats/casper,faizmokhtar/Fatso,AWCN/PrismCasper,hnarayanan/narayanan.co-casper,rkalis/roscasper,dzimchuk/Casper,dzimchuk/Casper,kennethormandy/hb-casper,khsing/Haze,mnitchie/Casper,Gasol/Casper,eidolem/casper,naggie/Casper,trunk-studio/Casper,makapen/Casper,chowp/ghost-theme,benbrandt/Casper-Ben,Teamtailor/Casper,ugurcan377/StayPuft,mistermark/Zeitgeist,osirisguitar/GhostMetalCoder,BrandwatchLtd/Casper,Teamtailor/Casper,cmwinters/lynx-theme,dlecina/StayPuft,dolph/Casper,notno/Casper,bsansouci/Casper,spencercree/customGhost,osirisguitar/GhostMetalCoder,DanPurdy/Spooky,vertigra/Ghostly,Acidburn0zzz/Casper,tiagocasanovapt/Casper,Rystakei/topdollar-theme,tylergibson/Tynker,bnggge/Casper,faizmokhtar/Fatso,alvareztech/Casper,Aplopio/ghost-theme,Gasol/Casper,RisingStack/StayPuft,therecluse26/Establishment,gchan/Casper,thormagnusson/casper,bisurance/bisurance-ghost-casper,kaychaks/casper,spencercree/customGhost,kaiqigong/Casper,lizequn/CasperByZzz,Gaisuru/StayPuft,janocat/StayPuft,danmindru/Casper,yaeda/Arizona,btaratutin/Magenta,tiagocasanovapt/Casper,Flink/Casper,DevL/Casper,thormagnusson/casper,dpiatek/ghost-blog-theme,tandrewnichols/dullahan,bnggge/Casper,Gimpneek/Casper2Pelican,Normegil/Casper,jgable/Casper,derherrg/Orion,Inchdev/blog-theme,derdela/Casper,lukevers/Casper,danmindru/Casper,TheFynx/StayPuft-Dark,cobbspur/Casper,brnz/hboiled,naggie/Casper,Robdel12/Casper,cwonrails/cwoncasper,whmii/Bao-House,fastefoundation/Frog,zanui/Casper,jaydez/Casper2,kaizvn/kMod-Casper,tandrewnichols/dullahan,lumir-mrkva/chytra-ucetni-theme,wolfstonecraft/wolfstonecraft.github.io,wolfstonecraft/wolfstonecraft.github.io,haakoo/Findlay,ghostchina/Casper-zh,hnarayanan/narayanan.co-casper,tiagojsalmeida/Kibosh-Ghost-Theme,kdelfour/kd.eu-theme,iT2afL0rd/Desper,fastefoundation/Frog,yshrsmz/Casper_yslibrary,yshrsmz/Casper_yslibrary,jbfriedrich/lazo,discordianfish/5pi_ghost_theme,notno/Casper,cshutchinson/twilightfactor,blt/Casper,CAYdenberg/StayPuft,haakoo/Findlay,JDevlieghere/JCasper,eduardochiaro/Casper-Light,mbillard/Casper,lizequn/CasperByZzz,pdsarin/ChamanLal,pdsarin/ChamanLal,rizowski/Theme,makerdiary/Casper,SiliCAT/Casper,Elethom/Casper,Arasthel/Ghostly,TryGhost/Casper,derdela/Casper,evitolins/CasperEV,Ramshackle-Jamathon/Casper,evitolins/CasperEV,bisurance/bisurance-ghost-casper,ryexley/Casper,RuiAAPeres/Casper,benbrandt/Casper-Ben,martinnormark/Casper,tandrewnichols/casper-dev,hiroqli/Casper,AWCN/PrismCasper,steinwaywhw/ghost-theme,sealake/Ghostly,Soares/mindingourway.theme,allenan/mcs,yo1dog/Casper,arangas/StayPuft,cshutchinson/twilightfactor,tmack8001/skeletor-casper,ImKcat/ImKcatCasper,trunk-studio/Casper,1cookco/Casper,Kdecherf/Nicholas,PDXIII/Casper-FormMailer,renattomachado/StayPuft,johanderohan/Casper,topaxi/TopaxiCodes,halfdan/Casper,sawilde/Casper,jasperla/ghost-Jasper,Elethom/Casper,sealake/Ghostly,forfuturellc/Casper,Ramshackle-Jamathon/Casper,panezhang/Casper,adelq/tufte-ghost,jbfriedrich/lazo,kaiqigong/Casper,HiveHQ/Hive-Casper,devillex/phantasm,aholmes/Casper,HiveHQ/Hive-Casper,brnz/hboiled,duyetdev/islab-theme,bmancini55/Casper,eidolem/casper,paulcbetts/Casper,ghostchina/Casper-zh,carlosbaraza/devmind-ghost-theme,ticoombs/SeoBro,matitalatina/Casper,teambition/Casper,PDXIII/Casper-FormMailer,topaxi/TopaxiCodes,blade254353074/casper-custom,teambition/Casper,moehabib/casper-moe,SiliCAT/Casper,abr4xas/Casper2Pelican,johanderohan/Casper,cwonrails/cwoncasper,novaugust/Novasper,rkalis/roscasper,ITJesse/Casper-zh,panezhang/Casper,arangas/StayPuft,velimir0xff/Casper,sshockwave/VSCodeTheme,haakoo/Findlay,Samisdat/ghost-conway,bttf/Casper,lumir-mrkva/chytra-ucetni-theme,ticoombs/SeoBro,happyfunboy/ghost_theme,molly/ghost-theme,10hacks/blog-theme-casper,netputer/Casper,martinnormark/Casper,Soares/mindingourway.theme,tenoku/boo,JulienBrks/Casper,codio/Casper,chowp/ghost-theme,oddui/casper_littlehorse,ITJesse/Casper-zh,ivanvanderbyl/nord-theme,Arasthel/Ghostly,novaugust/Novasper,wolfstonecraft/wolfstonecraft.github.io,yuchien302/YuChienGhostTheme,adelq/Casper,emmmile/Casper,jaydez/Casper2,jacksoncwwong/Casper