Freestyle: removed the dummy implementation of a texture manager.

Legacy texture shaders from the original stand-alone Freestyle program are also
declared as deprecated, in favor of Blender's new line style textures.

Patch contribution by Paolo Acampora.  Thanks!
Get rid of custom tooltip for pushdown button
Bugfix: Bend modifier's angle property has crazy limits

As reported by ZanQdo on IRC, the bend modifier's "angle" property had a range
of +/- 572.95 degrees (equivalent to 10 radians). From the looks of things, this
was simply something overlooked when doing degrees to radians conversions. Now
it has a range of +/- 180 degrees.
Remove redundant NULL check
Fix crash binding mdef with no faces
Fix T40052, Grid Particles Crash due to invalid empty mesh verts access
for bbox calculation.
Fix for dropping images into the 3D View
- wasn't allocing image-user.
- wasn't managing user counts.
Fix T40051: Inconsistent dupli vert/face handling of group member types
playanim: check for escape key while loading images

(todo from 2.4x)
Fix T40033: Jumping between versions can lead to loss of node storage
data.

Saving a file with a new blender node that uses bNode->storage data and
then loading that in an older version will make the node undefined, but
still retain the original type identifier (in case it is defined later).

If the file is then saved over and loaded again in the newer version,
where the node type is defined, it won't have a valid storage struct.
To handle such cases gracefully, check if storage data is expected but
doesn't exist when initializing node types. User then at least get a
chance of fixing the problem manually.

Suggested fix by @brecht.
Cycles-Bake: Ambient Occlusion needs to be computed for COMBINED

Now the COMBINED pass includes the Ambient Occlusion.

This was not reported anywhere, but while working in the Subsurface Scattering I realize we needed this fix for combined.