[Bf-python] Image attributes

[Ed Blake]

In 2.43 image handling was changed.  Yesterday I needed to update a import
script that worked with image texture attributes that no longer exist.  The
problem is their functionality hasn't been replaced by anything in the image
module!

Here are a few things that are missing:
There is no way to set image type - movie and internal are set automatically,
but how do you tell Blender your image is part of a sequence?
No way to set movie/sequence length, and image.end is broken - currently
image.start/image.end only take values between 1 and 127?  Was this ever a
real limitation in Blender?
No access to the (new) Auto-Update feature.

It's too bad I didn't test this before the release, I just assumed that since
the old API was removed at least whoever removed it knew that the image
module needed to be updated.  Now it is too late and the API is less capable
than in the previous version :(

Anyway, I can do some try/except blocks in the importer once I know what the
new methods look like.  That way the script will at least work for people
using CVS/future versions.