Fixed Wave file loading in Highlife when long is not 32 bits

This fix simply changes the types used in HighLifeRiffWave.{cpp,h} to use
portable <cstdint> types, making Wave file loading work in environments where
long is not 32 bits. Only tested on Linux.
Added Google C++ testing framework
Tweaked the Google test Makefile

The sample unit test was not building correctly,
http://stackoverflow.com/questions/10315016/error-during-making-gtest
cleared things up.
Added build & clean targets for Google test library
Copy the Google test library into the libs directory after making it
Add test for WAV file loading in Highlife