Require at least one query layer on search.

Closes #66
Removed "." from underscore.string package location.

Hopefully fixes jasmine tests on travis.
Reworked underscore.string import to see if it imports on travis.
Removed underscore.string.
Added xstyle back into bower.json.
Merge pull request #79 from agrc/require-query-layer

Require at least one query layer on search.