Readme: fix line-through on github
Readme: fix line-through on github

GitHub's Markdown rendering puts a border line below the headline.
Unfortunately, that stroke through the "then" badge. Raising it above
the build status or same height should fix this.
Moved bird logo down into the "Features" section for same reason.

Minor: Remove "Features:" colon to fit other headlines' style.
Minor: Replace U+0303 combining tilde with HTML asymp.

justsml/bluebird,enicolasWebs/bluebird,timnew/bluebird,amelon/bluebird,joemcelroy/bluebird,DrewVartanian/bluebird,robertn702/bluebird,soyuka/bluebird,DeX3/bluebird,henryqdineen/bluebird,peterKaleta/bluebird,linalu1/bluebird,esco/bluebird,moretti/bluebird,peterKaleta/bluebird,robertn702/bluebird,DrewVartanian/bluebird,STRML/bluebird,mdarveau/bluebird,bjonica/bluebird,janmeier/bluebird,bjonica/bluebird,ankushg/bluebird,codevlabs/bluebird,Scientifik/bluebird,ajitsy/bluebird,ronaldbaltus/bluebird,sandrinodimattia/bluebird,bsiddiqui/bluebird,tesfaldet/bluebird,impy88/bluebird,arenaonline/bluebird,n1kolas/bluebird,bsiddiqui/bluebird,developmentstudio/bluebird,lindenle/bluebird,migclark/bluebird,whatupdave/bluebird,xdevelsistemas/bluebird,justsml/bluebird,fmoliveira/bluebird,sandrinodimattia/bluebird,timnew/bluebird,johnculviner/bluebird,tpphu/bluebird,satyadeepk/bluebird,davyengone/bluebird,cusspvz/bluebird,fmoliveira/bluebird,bjonica/bluebird,lindenle/bluebird,perfecting/bluebird,starkwang/bluebird,cgvarela/bluebird,esco/bluebird,joemcelroy/bluebird,ryanwholey/bluebird,avinoamr/bluebird,ricardo-hdz/bluebird,moretti/bluebird,akinsella/bluebird,BigDSK/bluebird,xbenjii/bluebird,alubbe/bluebird,soyuka/bluebird,P-Seebauer/bluebird,djchie/bluebird,P-Seebauer/bluebird,ryanwholey/bluebird,xdevelsistemas/bluebird,johnculviner/bluebird,perfecting/bluebird,lo1tuma/bluebird,soyuka/bluebird,DrewVartanian/bluebird,HBOCodeLabs/bluebird,briandela/bluebird,javraindawn/bluebird,janmeier/bluebird,TechnicalPursuit/bluebird,code-monkeys/bluebird,TechnicalPursuit/bluebird,tesfaldet/bluebird,angelxmoreno/bluebird,developmentstudio/bluebird,HBOCodeLabs/bluebird,Zeratul5/bluebird,yonjah/bluebird,timnew/bluebird,mcanthony/bluebird,ajitsy/bluebird,mdarveau/bluebird,perfecting/bluebird,alubbe/bluebird,ankushg/bluebird,garysye/bluebird,DeX3/bluebird,haohui/bluebird,enicolasWebs/bluebird,BridgeAR/bluebird,gillesdemey/bluebird,kjvalencik/bluebird,StefanoDeVuono/bluebird,xbenjii/bluebird,djchie/bluebird,briandela/bluebird,impy88/bluebird,ricardo-hdz/bluebird,dantheuber/bluebird,gillesdemey/bluebird,arenaonline/bluebird,BridgeAR/bluebird,lo1tuma/bluebird,wainage/bluebird,starkwang/bluebird,RobinQu/bluebird,petkaantonov/bluebird,tpphu/bluebird,Scientifik/bluebird,ryanwholey/bluebird,whatupdave/bluebird,mcanthony/bluebird,ziad-saab/bluebird,fadzlan/bluebird,paulcbetts/bluebird,techniq/bluebird,bsiddiqui/bluebird,janmeier/bluebird,avinoamr/bluebird,dantheuber/bluebird,janzal/bluebird,atom-morgan/bluebird,starkwang/bluebird,lindenle/bluebird,davyengone/bluebird,ziad-saab/bluebird,akinsella/bluebird,javraindawn/bluebird,garysye/bluebird,janzal/bluebird,kidaa/bluebird,robertn702/bluebird,ankushg/bluebird,briandela/bluebird,janzal/bluebird,alubbe/bluebird,ScheerMT/bluebird,Zeratul5/bluebird,kidaa/bluebird,gillesdemey/bluebird,JaKXz/bluebird,STRML/bluebird,ScheerMT/bluebird,naoufal/bluebird,TechnicalPursuit/bluebird,lo1tuma/bluebird,linalu1/bluebird,xdevelsistemas/bluebird,vladikoff/bluebird,rrpod/bluebird,angelxmoreno/bluebird,mcanthony/bluebird,ricardo-hdz/bluebird,JaKXz/bluebird,techniq/bluebird,whatupdave/bluebird,moretti/bluebird,vladikoff/bluebird,wainage/bluebird,jozanza/bluebird,justsml/bluebird,P-Seebauer/bluebird,tesfaldet/bluebird,kjvalencik/bluebird,atom-morgan/bluebird,HBOCodeLabs/bluebird,paulcbetts/bluebird,garysye/bluebird,kjvalencik/bluebird,javraindawn/bluebird,mdarveau/bluebird,code-monkeys/bluebird,n1kolas/bluebird,haohui/bluebird,matklad/bluebird,BigDSK/bluebird,Scientifik/bluebird,techniq/bluebird,fmoliveira/bluebird,ydaniv/bluebird,enicolasWebs/bluebird,developmentstudio/bluebird,petkaantonov/bluebird,arenaonline/bluebird,matklad/bluebird,cusspvz/bluebird,goopscoop/bluebird,rrpod/bluebird,illahi0/bluebird,jozanza/bluebird,esco/bluebird,fadzlan/bluebird,JaKXz/bluebird,n1kolas/bluebird,code-monkeys/bluebird,abhishekgahlot/bluebird,codevlabs/bluebird,cgvarela/bluebird,ajitsy/bluebird,RobinQu/bluebird,goofiw/bluebird,DeX3/bluebird,cwhatley/bluebird,rrpod/bluebird,RobinQu/bluebird,reggi/bluebird,ziad-saab/bluebird,johnculviner/bluebird,atom-morgan/bluebird,goopscoop/bluebird,STRML/bluebird,angelxmoreno/bluebird,BridgeAR/bluebird,wainage/bluebird,amelon/bluebird,kidaa/bluebird,xbenjii/bluebird,dantheuber/bluebird,fadzlan/bluebird,ydaniv/bluebird,Zeratul5/bluebird,migclark/bluebird,satyadeepk/bluebird,paulcbetts/bluebird,yonjah/bluebird,migclark/bluebird,vladikoff/bluebird,matklad/bluebird,petkaantonov/bluebird,satyadeepk/bluebird,avinoamr/bluebird,ydaniv/bluebird,joemcelroy/bluebird,naoufal/bluebird,abhishekgahlot/bluebird,BigDSK/bluebird,amelon/bluebird,davyengone/bluebird,yonjah/bluebird,a25patel/bluebird,cgvarela/bluebird,StefanoDeVuono/bluebird,StefanoDeVuono/bluebird,illahi0/bluebird,Wanderfalke/bluebird,sandrinodimattia/bluebird,illahi0/bluebird,goopscoop/bluebird,reggi/bluebird,goofiw/bluebird,cwhatley/bluebird,naoufal/bluebird,cwhatley/bluebird,haohui/bluebird,djchie/bluebird,reggi/bluebird,ronaldbaltus/bluebird,henryqdineen/bluebird,linalu1/bluebird,Wanderfalke/bluebird,abhishekgahlot/bluebird,cusspvz/bluebird,Wanderfalke/bluebird,tpphu/bluebird,a25patel/bluebird,jozanza/bluebird,a25patel/bluebird,ronaldbaltus/bluebird,goofiw/bluebird,henryqdineen/bluebird,impy88/bluebird,ScheerMT/bluebird,akinsella/bluebird,peterKaleta/bluebird,codevlabs/bluebird