Updated ReadMe with links to the new Contributing page.
Updated ReadMe with links to the new Contributing page.

- This is a follow-on change from PR #1131

- Updated the main ReadMe with link to the new Contributing page on website http://dotnet.github.io/orleans/Contributing

- Fixed some broken content / layout, and cleaned up some crufty wording.

LoveElectronics/orleans,Liversage/orleans,galvesribeiro/orleans,dVakulen/orleans,brhinescot/orleans,sergeybykov/orleans,tsibelman/orleans,yevhen/orleans,gabikliot/orleans,xclayl/orleans,amccool/orleans,jdom/orleans,rrector/orleans,ElanHasson/orleans,ibondy/orleans,gabikliot/orleans,shlomiw/orleans,jdom/orleans,shayhatsor/orleans,yevhen/orleans,rrector/orleans,jokin/orleans,amccool/orleans,bstauff/orleans,amccool/orleans,ashkan-saeedi-mazdeh/orleans,ElanHasson/orleans,sebastianburckhardt/orleans,ReubenBond/orleans,ticup/orleans,Carlm-MS/orleans,waynemunro/orleans,tsibelman/orleans,dotnet/orleans,dotnet/orleans,brhinescot/orleans,kylemc/orleans,MikeHardman/orleans,Carlm-MS/orleans,kylemc/orleans,Liversage/orleans,shlomiw/orleans,hoopsomuah/orleans,hoopsomuah/orleans,galvesribeiro/orleans,ibondy/orleans,shayhatsor/orleans,pherbel/orleans,Liversage/orleans,pherbel/orleans,SoftWar1923/orleans,centur/orleans,dVakulen/orleans,centur/orleans,jkonecki/orleans,jthelin/orleans,benjaminpetit/orleans,jason-bragg/orleans,Joshua-Ferguson/orleans,Joshua-Ferguson/orleans,gigya/orleans,SoftWar1923/orleans,jokin/orleans,waynemunro/orleans,ticup/orleans,ashkan-saeedi-mazdeh/orleans,veikkoeeva/orleans,gigya/orleans,LoveElectronics/orleans,jkonecki/orleans,brhinescot/orleans,MikeHardman/orleans,xclayl/orleans,sergeybykov/orleans,jokin/orleans,ashkan-saeedi-mazdeh/orleans,sebastianburckhardt/orleans,dVakulen/orleans,bstauff/orleans