Update F# to match dev15.6 preview 4
Update F# to match dev15.6 preview 4

svick/cli,johnbeisner/cli,dasMulli/cli,dasMulli/cli,svick/cli,dasMulli/cli,johnbeisner/cli,johnbeisner/cli,livarcocc/cli-1,livarcocc/cli-1,svick/cli,livarcocc/cli-1