Case-insensitive searches for all keys

[spacepod]

Addama should support case insensitive searches through the REST API. As a technology, mongodb's build-in "case-insensitive regex search with anchors" will be used. Initially, this will be applied to all fields for now. Behavior for REST calls with union/intersection should remain the same: for example.?gene=A&gene&B&source=GEXP&source=Meth
logically translates to
("Gene A" OR "Gene B") AND ("source GEXP" OR "source METH")