Update to most recent freetype & freetype-gl

[ColinGilbert]

I updated the freetype and freetype-gl versions to the most recent. It required adding the ftgl namespace to all C++ files.

I also made the freetypeglxx namespace explicit for all identifiers in the demo app, but that is not necessarily required (simply good style.) Tested on my system :)

[henriquegemignani]

The build failed here, on visual studio 2013 x64.
Failed to find the ft2build.h file (on texture-font.c)

Please note that on master, the embedded freetype lib had a custom made CMakeLists.txt that just compiled the necessary portions of freetype, generating a CMake target. Also, this target exported the necessary include_dirs via target_include_directories.

With the update, it seems the freetype project provides it's own CMakeLists.txt, but it doesn't use target_include_directories on the generated target (after all, it is a new feature from CMake 2.8.11).

Oh, disregard the travis failure.

[ColinGilbert]

I copied over the old CMakeLists.txt from freetype-gl, so it should be the same.

[henriquegemignani]

The issue is with freetype, not freetype-gl.