Updated README with info on SubilmeLinter3.
Updated README with info on SubilmeLinter3.

tangledhelix/SublimeLinter-for-ST2,uschmidt83/SublimeLinter-for-ST2,tangledhelix/SublimeLinter-for-ST2,SublimeLinter/SublimeLinter-for-ST2,biodamasceno/SublimeLinter-for-ST2,uschmidt83/SublimeLinter-for-ST2,biodamasceno/SublimeLinter-for-ST2,SublimeLinter/SublimeLinter-for-ST2