bugfix: added the missing prev_job_id accessor method; also added a call to if from new()
cosmetic: direct the debug output of BaseAdaptor to STDERR instead of STDOUT
bugfix: stop printing overflow-related debug output to STDOUT; interface with overflow adaptor simplified
let Job.input_id stringify itself
ObjectAdaptor is now overflow-aware and can store longer blobs transparently
store a Job using BaseAdaptor's store() method
bugfix: no hope for other DBD drivers to support detection of auto-incrementing fields => use our inernal fixed rule