Implement empty string query
Merge branch '0.9.0-wip' into f/empty-string-query
Add unit test for empty string query
Merge branch '0.9.0-wip' into f/empty-string-query

Conflicts:
	test/spec/unit/QuerySpec.js
Do empty string queries with equals and notEquals
Merge pull request #47 from stackmob/f/empty-string-query

Empty string query