Change default setting for reserved PSF objects
processCoadd: set detection to use the declared variances

In detection on a coadd, we typically want to normalise out
the (sometimes extreme) differences in depth over the image
due to dithers.
ingest: permissions should be specified in octal

Specifying the permissions without using octal leads to
the bizarre: --w--wx--T .
ingest: silently ignore mkdir failures due to race conditions

The directory may have been created by another process.
move CalibrateTask from ProcessImageTask into ProcessCcdTask

CalibrateTask seems to have been included in ProcessImageTask before the
days of CoaddPsf, when we needed to be able to generate a Psf for a coadd
using the coadd; this is no longer necessary, and its presence in
ProcessImageTask stands in the way of further refactoring to support the
plan for coadd multi-band deblending and measurement.

In order to implement matching between the detected sources and the
reference catalog, I've added an AstrometryTask to ProcessCoaddTask, since
it can no longer rely on the one in CalibrateTask.  This change does
change the config hierarchy, and so will break use of processCcd on
data repositories with existing data (if not using "--clobber-config").
astrometry: instantiate AstrometryTask.astrometer when needed

ProcessImageTask needs the 'astrometer' to be instantiated, which was
previously done by the CalibrateTask.  Now we can't rely on that, as it
was moved.
make failure to match sources non-fatal

Allows us to push forward with processing, providing something that might
be useful.
Add polygon to tempExp files.
Merge branch 'tickets/HSC-976'
Add multi-band coadd processing Tasks
Merge branch 'tickets/HSC-1060'
Include differential background from detection phase in persisted backgrounds
Persisting the backgrounds does not merit a warning.
Merge branch 'u/jbosch/HSC-1085'
Need to reset ProcessCcdTask's schema to include fields propagated from calibrate

SchemaMapper doesn't modify the output Schema it's given in-place - it makes a
copy and modifies that.  Because ProcessImageTask was looking at self.schema,
which did not include the flag fields propagated from output fields, when we were
setting those we'd be mucking up the data in the next record (and if we ever tried
to do this on the last record, we'd could get a segfault).