GRAPHICS: Add support for different states in NWN models

No animations yet, though.
NWN: Set the correct model state for doors and placeables
GRAPHICS: Add support for animations in NWN models
GRAPHICS: Add showBoundingBox() to Renderable
GRAPHICS: Add support for picking objects
NWN: Hook up object picking again
GRAPHICS: Fix transparency blending

Depth writing needs to be disabled for transparent materials.

The material now has a transparency hint member, ideally
read from the model. If the model does not provide a hint
the transparency is inferred from the textures and diffuse
color. Since Aurora textures compressed with DXT1 are always
opaque, we override the default Ogre claim that DXT1 textures
have an alpha channel.
GRAPHICS: Fix materials with multiple textures

Contrary to what I thought, the texture coordinate set
is not automatically incremented for every unit state.
GRAPHICS: Move creating model entities into class Model
GRAPHICS: Add back support for KotOR/KotOR2 models
GRAPHICS: Add some extra sanity checks when loading images
KOTOR: Add back modules and areas with doors and placeables
KOTOR2: Add back modules and areas with doors and placeables
ENGINES: Enable free look when pressing the middle mouse button
NWN: Start adding back creatures

No creatures of model type P (segmented models) yet.
KOTOR: Start adding back creatures

Only bodies, no heads, for segmented models at the
moment, though.
GRAPHICS: Fix creation of solid color materials
GRAPHICS: Add back video playing

This time, the video player can be easily adopted to play
several videos simultaneously. This will be necessary
for Sonic.

Right now, we still de-YUV the videos onto a surface held
in CPU memory, and then copy (with pixel format conversion)
it into video memory. This is not optimal and we should
probably change it to de-YUV directly onto the video
memory.
ENGINES: Hook up video playing again
GRAPHICS: Move createNode() into class Model