Initial files for PVRTC encoder. Starting with a decompressor.
Add PVRTC Pixel class

This class accepts a pixels with up to 8-bit components. With the way PVRTC is laid out, there are many different bit modes that we could run into. This lets us change between any that we'd like to deal with.
Reorder color channels to match PVRTC spec
constify some method declarations
Add block definitions for PVRTC
Add a logical definition of an image for PVRTC
Constify a few things
If we want a color channel with zero depth then it should default to full intensity, but we will remember that there is zero depth there.
Pixel depth defaults to 8
Add accessors for the color channels and a method for packing the information into a 32 bit RGBA int
First pass at PVRTC Decompressor
Add GTest framework
Tell CMake to look in individual test directories for tests if they exist
Merge branch 'master' into PVRTCDecoder to use GTest

Conflicts:
	CMakeLists.txt
Add block tests
Bugfix

The bug was that bitIdx was not being taken into account when we realized that there was enough pixel depth to stay within the current byte when reading pixel values.
Add preliminary tests for PVRTC pixels
Fix bug where the defaulted value caused a crash (wtf?)
Fix some compiler warnings.
Begin counting the bits from the beginning of the byte stream. The way I was doing it before was silly...