State: added STATE_PRE_QA
QAState: added in a JSAQAState class (like JSAProcState)
DB: created access and update methods for qa table.

Also moved some functions around, updated other methods to use
the new qa_state column in find jobs, updated the change_state
method to alter the qa_state if a job is being reprocessed, and
updated the test_db files to test this.