Typos in config files

This week I've made a couple of minor changes to the way the iterative map-maker handles configuration files. On too many occasions I've made a change to a config parameter and seen no effect because of a typo or else I've left a parameter unspecified and had no idea what that really meant.

We've now fixed both these problems:

• Defaults are now read from a file called $SMURF_DIR/smurf_makemap.def
• When user-supplied parameters are read in they are merged with the defaults and if there is any keyword used that is not present in the default file you will get an error immediately.
• When the history is written out (use KAPPA HISLIST to see it) it contains the values that were actually used rather than just the values that were supplied by you. These are much more useful when trying to work out exactly what is different between two reductions.

I did have to change the way config files work in one small way. Previously if you wanted your config file to include overrides based on the wavelength you would have to say "flt_850.something" or "flt_450.something". To allow the above changes to work we've had to reorganize that slightly so you now say "450.flt.something" and can now override all the normal parameters in this way for a particular wavelength.