removed unused variable to make it compile on windows - cp35575
Fixed Common.proj so the solution compiles on latest Mono

The file incorrectly overrode some properties (likely as a workaround for some early versions of Mono) that made the build fail.
ast returned from compile will no longer contain superfluous unary + and -

fixed cp35572
corrected exception thrown from socket.create_connection

fixed cp35578, cp35388
Merge remote-tracking branch 'paweljasinski/cp35572' into ipy-2.7-maint
Merge remote-tracking branch 'paweljasinski/cp35576' into ipy-2.7-maint
Merge remote-tracking branch 'akoeplinger/mono-ipy-2.7-maint' into ipy-2.7-maint
Merge remote-tracking branch 'fdanny/socket_updates' into ipy-2.7-maint