Add support of C++11

Hello!

C++11 will be more popular, so, I think it would be better if you add new property to cpp module like dialect or standard. This property may have values like c++03, c++11, c++14 and other. I think that more projects uses new C++ and it is better to have such property to eliminate necessity of specifying compiler options like -std=c++11 which depend on used compiler. Also it is good idea to have such property for C (C99, C11).

Thank you!