Bug 1098512 - field filters work with url fields

Mid-way through a refactor to correct a lot of confusing code.  Query
String is now the source of truth on filtering.
Bug 1098512 - check box filters work again

This is more heavy refactoring to make the queryString the single
source of truth.  Still not quite done, but this simplifies a fair bit
of code.  I also changed the ``isClassified`` to not be just ``true``
and ``false`` but used ``classified`` and ``unclassified`` as the
values as boolean was confusing.
Bug 1098512 - Code cleanup and refactoring.

Removed dead and redundant code.  Fixed names of functions to be more
clear.  Rearranged function placement to be more logical.
Bug 1098512 - more code cleanup for comments
Bug 1098512 - made searchQuery work like a field filter

This fixes lots of issues found in a code-review with mdoglio.
1. roll the string search query into working like a normal field
filter, so it doesn’t require as much special handling.  It’s still a
bit special because it’s a string that gets split and checked with
substrings.  But much cleaner now.  Was able to remove a watch as well.
2. split the ``_checkFilters`` into separate ``_checkXXX`` functions to
make it clearer.
3. moved the filter handling of onLocationChangeSuccess into
``jobfilters.js`` because it belongs there.
4. caching the various values of the filters once each time they
change, rather than re-working them on each job during filtering.
Bug 1098512 - add refilter when search string is cleared
Bug 1098512 -  fix field filters - they were munging the case
Bug 1098512 -  fix startsWith error on Chrome

* also removed the “search string” option for the field filters menu
drop-down.