removed ambiguous parameter "set_by_user" from many places in codebase,
renaming it to be upload_bake, which is a more accurate descriptor.
This allowed me to see several inconsistencies in how this variable was
being set - these errors were also fixed. User-visible result should be
that baked textures are not reuploaded on changing avatar sex until the
save button is pressed. primary win here is code clarity.

Code reviewed by Bigpapi.

No expected functionality change; this mostly contains cosmetic cleanup.

Reviewed by: Nyx

merging in new wearable infrastructure to get a step closer to eventually supporting multiple wearables per type. Merge tested and compiles/working on linux and windows - no obvious regressions on appearance or appearance editor. Merge generated no conflicts due to being tested in fresh re-branch in avatar-pipeline/multiple-textures-12. Merge perfomed with following command:

svn merge -r 136489:136510 svn+ssh://svn.lindenlab.com/svn/linden/branches/avatar-pipeline/multiple-textures-12 .

Progress can be tracked in DEV-32551.

 -Nyx

ignore-dead-branch