Prevent memory leak during search indexing.

See #457.
Avoid "merge" comment lines in .pot.

Also, switch to long-form arguments to be clearer about what's being set
for xgettext.
Set server vars to null if not set.

Prevents undefined index notices when running background processes.
Fix _log calls in backgrounded jobs.
Pull in Coins background fix.
Remove separate processes.log.
Leave background-size setting to theme css.
Close container div and use sections for content and sidebar areas. Fix #460.
Remove extra padding from item list on items/batch-delete.
Clean up subnavigation padding rules and style for moble widths.
Use subnavigation mobile style on viewports up to 767px in width.
Fix mobile navigation dropdown gradient in IE.
Fix plugin translations for some locales.
Make search ids unique. Fix #464
Minor documentation addition to Omeka_Db_Table::fetchObject();
Merge branch 'master' of github.com:omeka/Omeka
Automatically add view helpers dir for plugins.
Update Coins submodule.
Fix full delete-confirm footer bug. Fix #467.
Add a bunch of missing delete-confirm classes.