Clean up README.md
Clean up README.md

- Remove redundant Readme in title
- Remove unnecessary Description header
- Move installation steps to immediately follow description
- Reword some parts for clarification
tntcrowd/ExoPlayer,bongole/ExoPlayer,luckcoolla/ExoPlayer,ebr11/ExoPlayer,Ood-Tsen/ExoPlayer,rubensousa/exoplayer-amazon-port,castlabs/ExoPlayer,KiminRyu/ExoPlayer,JasonFengHot/ExoPlayerSource,google/ExoPlayer,FinalLevel/ExoPlayer,rubensousa/exoplayer-amazon-port,reid-mcpherson/ExoPlayerDebug,jeoliva/ExoPlayer,ened/ExoPlayer,superbderrick/ExoPlayer,androidx/media,zhouweiguo2017/ExoPlayer,reid-mcpherson/ExoPlayerDebug,amzn/exoplayer-amazon-port,superbderrick/ExoPlayer,androidx/media,YouKim/ExoPlayer,ebr11/ExoPlayer,Furystorm/ExoPlayer,FinalLevel/ExoPlayer,Ood-Tsen/ExoPlayer,tntcrowd/ExoPlayer,MaTriXy/ExoPlayer,yangwuan55/ExoPlayer,YouKim/ExoPlayer,ened/ExoPlayer,tntcrowd/ExoPlayer,JasonFengHot/ExoPlayerSource,stari4ek/ExoPlayer,jeoliva/ExoPlayer,algrid/ExoPlayer,androidx/media,luckcoolla/ExoPlayer,saki4510t/ExoPlayer,superbderrick/ExoPlayer,PavelSynek/ExoPlayer,TheWeatherCompany/ExoPlayer,jcable/ExoPlayer,michalliu/ExoPlayer,zhouweiguo2017/ExoPlayer,YouKim/ExoPlayer,yangwuan55/ExoPlayer,martinbonnin/ExoPlayer,Furystorm/ExoPlayer,barbarian/ExoPlayer,Dysonics/ExoPlayer,algrid/ExoPlayer,KiminRyu/ExoPlayer,KiminRyu/ExoPlayer,ened/ExoPlayer,jeoliva/ExoPlayer,natez0r/ExoPlayer,google/ExoPlayer,FinalLevel/ExoPlayer,natez0r/ExoPlayer,WeiChungChang/ExoPlayer,TheWeatherCompany/ExoPlayer,stari4ek/ExoPlayer,YouKim/ExoPlayer,reid-mcpherson/ExoPlayerDebug,Ood-Tsen/ExoPlayer,WeiChungChang/ExoPlayer,michalliu/ExoPlayer,PavelSynek/ExoPlayer,jcable/ExoPlayer,JasonFengHot/ExoPlayerSource,luckcoolla/ExoPlayer,algrid/ExoPlayer,danikula/ExoPlayer,WeiChungChang/ExoPlayer,MaTriXy/ExoPlayer,saki4510t/ExoPlayer,MaTriXy/ExoPlayer,fanhattan/ExoPlayer,kiall/ExoPlayer,danikula/ExoPlayer,bongole/ExoPlayer,TheWeatherCompany/ExoPlayer,barbarian/ExoPlayer,michalliu/ExoPlayer,ClubCom/AndroidExoPlayer,pittenga/ExoPlayer,fanhattan/ExoPlayer,Dysonics/ExoPlayer,ebr11/ExoPlayer,zhouweiguo2017/ExoPlayer,pittenga/ExoPlayer,castlabs/ExoPlayer,yangwuan55/ExoPlayer,pittenga/ExoPlayer,martinbonnin/ExoPlayer,kiall/ExoPlayer,jcable/ExoPlayer,amzn/exoplayer-amazon-port,ClubCom/AndroidExoPlayer,martinbonnin/ExoPlayer,kiall/ExoPlayer,bongole/ExoPlayer,aravinds03/ExoPlayer,aravinds03/ExoPlayer,aravinds03/ExoPlayer,saki4510t/ExoPlayer,google/ExoPlayer,ClubCom/AndroidExoPlayer,natez0r/ExoPlayer,danikula/ExoPlayer,stari4ek/ExoPlayer,barbarian/ExoPlayer,PavelSynek/ExoPlayer,fanhattan/ExoPlayer,Furystorm/ExoPlayer,castlabs/ExoPlayer,rubensousa/exoplayer-amazon-port,Dysonics/ExoPlayer,amzn/exoplayer-amazon-port