- Changes to dictionaries() and pipehistory()

- The dictionaries() function automatically sorts files in the current
directory into global dictionaries based on what pipeline processes have
been run on them. It is important to sort each file into the proper
global dictionary -- the latter parts of the spectral reduction process
take precedence over earlier steps. For example, a flux-calibrated
science spectrum should not be sorted into the dispersion-corrected
science spectra global dictionary even though it is, in fact, a
dispersion-corrected spectrum. The pipeline was making this error which
caused issues when running pipeline tasks individually. I resolved the
issue by changing the 'if' statements in dictionaries() to a sequence of
if and elif statements, and more importantly, coding the sequence in
reverse order. For example, the pipeline first checks if a spectrum is
flux-calibrated, and if not, then it checks if it's
dispersion-corrected, and if not, then it checks if it's just an
extracted-only spectrum, and if not, then it checks if it's a
background-subtracted 2-D image, and so on.
- There's an option now to have all global dictionaries printed by
running individual tasks, then run pipehistory() by entering 0, and then
enter 0 to see the dictionaries instead of the 'RUPIPE' keyword.
- There were errors for a couple images when making changes to the
'RUPIPE' 0-header keyword. These errors prevented images from getting
sorted properly -- this is now fixed (see changes on github).