Teach doxygen about control field macros (#3014)

Also updated .gitignore; .inc files should *not* be ignored,
and this one also had a lot of cruft apparently copied over
from pex_policy.
Merge branch 'tickets/3014'
comparison: properly deal with NAN values (#3167)

Because NaN != NaN, a naive comparison of a Config containing a NaN
with itself would fail.  Need to treat NaN values specially.

Note that this does not change Config.__eq__, only Config.compare,
so for a Config containing a NaN:
    config == config ---> False
    config.compare(config) ---> True
Config: properly deal with NAN values in __eq__ (#3167)

Because NaN != NaN, a naive comparison of a Config containing a NaN
with itself would fail.  Need to treat NaN values specially.
Merge branch 'tickets/3167'
Merge remote-tracking branch 'lsst/master' into github