Update readme 
Update readme 

- Include links for preview builds from Bintray
- Include table with class libraries and features included on each build
- Add missing URL and mention to NETDUINO3_WIFI
- Amend name of QUAIL board to include Mikrobus name
Eclo/nf-interpreter,Eclo/nf-interpreter,nanoframework/nf-interpreter,nanoframework/nf-interpreter,Eclo/nf-interpreter,nanoframework/nf-interpreter,nanoframework/nf-interpreter,Eclo/nf-interpreter