Set Visual Studio CUDA build rule to false

* Set CUDA_ATTACH_VS_BUILD_RULE_TO_CUDA_FILE to false by default. Breaks VS builds when set to true.
Fixed setting CXX flags and MSVC version checks.

* Cherry picked from 89d27a636c4ce861e9233fcfaa2f832aa49d883b
Merge pull request #275 from kwaegel/vs2012

Vs2012 cmake fix