Fixes the wrangling of multiple tags at once

Another issue that keeps on giving: http://code.google.com/p/otwarchive/issues/detail?id=3911

Also:
* tags on the Tag Wranglings pages (aka mass bins) can now be wrangled to multiple fandoms at once, to mitigate the problem of crossover tags being put in only one of the fandoms
* more notice and error messages where needed and appropriate
* obliterates tabs and turns them into spaces
* changes hash syntax from rocket (=>) to colon (:) where I had already changed some rows
* changes " to ' around Ruby strings where possible (i.e. no interpolation in the string) (you have Ariana to thank for that ;P )
More fixes to mass wrangling

http://code.google.com/p/otwarchive/issues/detail?id=3911

* Use ```where``` instead of ```find_with_ids```, which is missing from this Rails.
* Make the various things in the controller a bit more separate

The tag wrangle action is more verbose than the tag_wranglings index: it lists the successful changes as well as the errors. This was on purpose, but can be changed if needed.
Merge pull request #1669 from CristinaRO/issue-3911-wrangle-to-fandoms

Issue 3911 wrangle to fandoms