Transition SQL queries to stored procedures.

[cmillion]

They are pretty much locked in now. Transitioning to SP will add marginally more security and allow for further optimization on the server side. There are a lot of queries in gQuery.py that are rarely used, if ever. We should first make sure that we have good regression test coverage, and then changing queries to SP starting with the most used ones. The most used queries are probably those for box and cone searches in sky coordinates and for computing effective exposure time, but we can check the server logs to be sure.