find_orb

Removed no-longer-needed sorting of observations

Updated list of observatories and version date

Interactive Find_Orb : Delete key removes the selected observations (you have to reload the original observation set to undo this).

'eph2tle.cpp' is a little brighter about skipping comments at the beginning of the input file

'geo_test.cpp' (test code for the geopotential code) now can be set to include only terms after a specified point. It also shows numerically differentiated forces, foc checking the analytically determined ones.