Fix bug in 1-letter TEMPO code lookups
Add utils.py, move functions into it.
timing_model: add MJDParameter, fix up associated calculations.
Merge branch 'scott'
Add simple pulse phase class.
Cleaned up SPICE calls and added one from observatories.py to it
renamed and cleaned up SPICE stuff.  DO NOT USE TABS!  Or camelCase! Yuck!
Added ability to parse sci notation for MJDs.  And MJD precision.
Fixed problem with time_to_mjd_string() and how it handled jd1
Fixed another bug with time_to_mjd_string -- jd2 can be negative
Added more general observatory clock corrections and ability to apply them
Added an assertion about the fractional part of the MJD
apply_clock_corrections() now applies TIME statements as well
Added ability to set the scale in time_from_mjd_string
Fixed ordering of lon/lat return values
Fixed order of lon/lat arguments and attempt to make them and delta_ut1_utc persist
Added some TEMPO2 time comparison tests
Changed perms
Added GEO_WGS84_to_ITRF routine and made GEO coords use Latitude and Longitude
Added first cut at observatory posns and vels.  Requires python ERFA: https://github.com/nirinA/erfa_python