id creation. Removes gtk and Utils dependencies, making the
database routines independent of gtk and gnome.
* src/ImgManip.py: add thumbnailing routines.
* various: thumbnailing changes and pychecker fixes
svn: r3888
* src/GrampsKeys.py: select appropriate backend
* various: switch from GrampsGconfKeys to GrampsKeys for normal usage
* src/GrampsIniKeys.py: Alternate backend using .ini files instead
of gconf
svn: r3873
