general: allow for multiple task names

Sometimes it's desirable to check for multiple task names at once if
the indicate the same step in processing - e.g. wcsmosaic and makemos.
PICARD: new primitive to perform sanity checks on input data

Currently this primitive only checks the history of the input file(s)
to determine whether a mosaicking step has been carried out. If so a
non-fatal error is issued to inform the user that the ITC-derived
values will be wrong.
PICARD: check for mosaicked/coadded data