get darwin into the c++11 game

This gets osx and ios compatible to c++11.

Assumes xcode6 toolchain and needs 

https://github.com/opdenkamp/xbmc-pvr-addons/pull/400 to be merged first.

On the jenkins side there is some work left to ensure build compatiblity with the helix branch. (easiest is to wait until we abandon helix building tbh - then its only some checkboxes in jenkins and we are done...).