Added -m to the encoder to allow exporting materials from FBX scenes
This is the initial check-in for the material exporting feature. (Currently incomplete)
Added FileSystem::dirname()

dirname() returns the directory name of the given path.
Changed Properties so that files can be loaded relative to the property file.

File paths in property files can now be relative to the working directory or the property file.
In the mesh sample, this means the texture path in the material file can be "res/duck-diffuse.png" or "duck-diffuse.png".
Merge branch 'next' of https://github.com/blackberry/GamePlay into next
Merge branch 'next' of https://github.com/blackberry/GamePlay into next
Merge pull request #962 from dgough/next

Updated the encoder to generate a material file (experimental)