changed event fixes
changed event fixes

Fixes for Mantis 760. Changes to match SL object Edit form changes:
- color changes now fire CHANGED_COLOR instead of CHANGED_TEXTURE
- alpha changes now fire CHANGED_COLOR instead of CHANGED_TEXTURE
- texgen mode (e.g. planar vs default) changes no longer fire an event

Note that SL does not send any changed events AT ALL for scripted
changes. Attempts to fix this broke existing content in SL. However,
InWorldz is already sending the changed events for scripted changes, so
the same concern does not apply here. See
https://jira.secondlife.com/browse/SVC-914 for more on the ordeal there
(summary in final comment at bottom).

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