Changed the mag range for bright planted sources.

iources are added to the images in 3 groups.
Bright sources, Slow faint source, Fast faint sources.
The Birght source range was set to be 21.0 to 23.5 but the OSSOS
observations typically start having flux and centroid problems
around 23.0.  The bight sources are used as a check of the
flux calibration so we need them to be bright enough to make good
flux measurements. astrom_mag_check.py sets this boundary
at 23.0 so putting it as 22.8 here ensures that the there are
enough bright sources for calibration.
Some small changed to code logic to be more correct.

- match_idx must be a masked array so check that it is.
- use the .mask astribute of the match_idx instead of the value to
determine if we found a match.
- print errors to log when they happen, not just exit.
- PEP-8 issues.. I like keeping the code compliant, make PyCharm happy.

Also, the order of the return was wrong, now we write the variables into
the tag in an order that seems intuitive to me.... ;-)
PEP-8 clean up.  Including put main into a method.
Made the default logging level INFO instead of DEBUG.

This program is getting stable, so DEBUG info not needed as much.
But we likely need more than INFO currently provides...
Merge branch 'master' of https://github.com/ijiraq/MOP