BlurFilter added

Added a directional gaussian blur filter that can be used for two-pass
blurring.
Merge pull request #383 from AndrewJo/master

BlurFilter added
Added support for "backsided" objects.

This essentially adds support for front-face culling as opposed to the
usual back-face culling. This will result in all front-facing polygons
to be culled and reveal the polygons on the "backside".
Merge pull request #399 from AndrewJo/master

Support for different cull modes
Fixed facet bug when front-face culling is used

When front-face culling is used, front-facing polygons were incorrectly
assumed to be counter clockwise.
Merge pull request #400 from AndrewJo/master

Fixed polygon facet bug for front-face culling mode
Added DirectionalLight support

The Bumpmap materials lacked support for directional lights.
Implemented usage of uLightColor

This conforms with previous changes to Phong and Diffuse, but color is
calculated per-vertex where possible.
Merge pull request #425 from Davhed/bumpmap-materials-fix

Bumpmap materials fix
Merge pull request #421 from Davhed/gouraud-light-color

Gouraud light color
Merge pull request #3 from MasDennis/master

Master merge