Basic frontend text search.
Better names for fields in text search, currently via mapping to internal field names.

Later we should probably rename at least some of the fields internally.
Text search is submitted properly from keyboard enter in the text box.
Removed some unused code.
Fixed event number output in the clustering log.
Fixed bug with updating a whoosh index in place during clustering that was causing some events to not have reference points.
Meged changes from master.
Disabled stemming on keyword field text searchs to avoid issues with person names.
Have the index store all fields so the cluster program doesn't drop the unstored ones.

We should come up with a better solution later so we don't have to store all fields.
Merge branch 'master' into textsearch
Text search alias for categories field.
Merge branch 'textsearch' of https://github.com/sfu-natlang/lensingwikipedia into textsearch

Conflicts:
	backend/cluster
Added Anoop's text search frontend help text.
Fix for text searches on ID fields (ie eventRoot).
Put the link to the whoosh query syntax documentaion back in the text search help.
Fix to get the predicate and role argument fields working with text search.
Typo fix.
Merge branch 'textsearch' of https://github.com/sfu-natlang/lensingwikipedia into textsearch
Merge pull request #78 from sfu-natlang/textsearch

Text search