Some bugfixes, also added public function for closer integration btwn GoogleTest & CTest, contributed by Dan Blezek.

Other minor changes:
* Enhanced documentation & added examples
* _INCLUDE_DIRS and _LIBRARIES was being set regardless of _FOUND
* Fixed status message to include library rather than include dir
* Improved detection of MSVC compiled libraries
* Added a variable (GTEST_BOTH_LIBRARIES) for libgtest + libgtest_main