Remove some spurious imports from recindex.py.
Remove some obsolete code checking for old gtk versions.
Small fix to ui/catalog/README.
In Batch Editor, replace "Servings" by "Yield" and "Yield Unit" rows.

Fixes #332.
Translate attributes in batch editor's confirmation message box.
Fix batch editing of categories.

Fixes 333.
Update *.po[t] files.