[Qt-creator] C++11 in Creator's source: Update required features

[Koehne Kai]

> -----Original Message-----
> From: qt-creator-bounces+kai.koehne=theqtcompany.com at qt-project.org
> [...]
> I thus suggest requiring the subset of C++11 that is implemented by VS 2013,
> g++ 4.7 and clang 3.1 in master.

Another +1. Being able to use almost all C++11 features inside QtC is not only good for the Qt Creator developers, and the Qt Creator code base. It makes it also more likely Qt Creator gets even better support for editing C++11 :)

Kai