Bump up CMake version of OALwrapper

[PatrickHoward]

Saw this message when getting a version of the engine setup:

CMake Deprecation Warning at Strife.Engine/OALWrapper/CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.

We should consider bumping up the version of OAL to 2.8.12