Extended build information output and reference build type

Extended build information output and reference build type

mdrun -version (and -version flag for other binaries as well) now
contains more information about what was compiled in, as well as
compiler information and versions of external libraries used.
Also added C++ compiler information to mdrun log output.
When GPU builds are enabled there is also version information
about CUDA SDK, nvcc, driver and runtime.

A new "Reference" build type has been added to CMake. This turns
off lots of options and should be used when generating reference
values for our regression tests.

Change-Id: I7532bebdaeb1207c4f6e69d422b0f13da83e3960