Support free text messages.
Support free text messages.

While there's not any binary parsing to do, again support these removes
errors when running on collections of data from NCDC. Support here
required modifying the wmo regex for another category, saving the
category (SDUS, etc.) to check later, and using a category of NOUS
to trigger the FTM parsing.

dopplershift/MetPy,jrleeman/MetPy,Unidata/MetPy,dopplershift/MetPy,ahaberlie/MetPy,ShawnMurd/MetPy,ahill818/MetPy,jrleeman/MetPy,Unidata/MetPy,deeplycloudy/MetPy,ahaberlie/MetPy