SIP test suite revitalization

squashed: https://git.evergreen-ils.org/?p=working/SIPServer.git;a=shortlog;h=refs/heads/collab/phasefx/concerto

granular scratchwork: https://git.evergreen-ils.org/?p=working/SIPServer.git;a=shortlog;h=refs/heads/collab/phasefx/concerto-wip

My goal here was get the test suite working again such that it passed against both SIPServer and Bill's SIP2Mediator. To that end, I've switched the tests over to expecting the concerto test dataset to be in use for the Evergreen instance being tested.

Currently, not all of the tests pass, but that's no worse than the status quo. The point of contention is whether we be returning patron data when supplied with an invalid password (not for the SIP connection, but for the patron themselves). The tests, and the WIP for SIP2Mediator, expect an empty string to be returned with the otherwise mandatory field for such conditions.

Not yet putting a pullrequest on this, though a lot of WIP builds off of it.