Fix backwards compatibility in CoaddPsf FITS I/O
Merge branch 'u/jbosch/DM-944'
add sourceRecalibrate routine to convert shapes to be wcs based.
Merge branch 'u/bick/HSC-959'
ExposureRecord: include aperture correction in assignment.
copyWithinFootprint: respect image size

copyWithinFootprint could produce a segfault (or at least corrupt
memory) when copying a Footprint that is larger than either of the
images.  Changed so that pixels outside either image are ignored
(i.e., it copies every pixel it is able to).  Added test of this
behaviour and documented the function's behaviour.
copyWithinFootprint: add consts in implementation
Polygon: Add table based persistance for Polygon.

This required a split of the Python wrappers for Polygon into a separate module, in its
own namespace, to resolve a circular dependency.  As part of this, Polygons are now passed around
by shared_pointer instead of by-value.
Merge branch 'tickets/HSC-972'
Exposure: Add a Polygon object to Exposure.

Polygons will be used to define valid regions for each CCD to
reject vignetted regions when building the Coadd Psf.
Merge branch 'tickets/HSC-973'
Merge branch 'tickets/HSC-1004'