Added rc_file_defaults() to reset matplotlib parameters
Changed sizes and colors of symbols
Now survey saves the original LST as survey.LST_Obs

In the past, the survey instance only saved the stating and ending
times of the observation but not the LST from which that tile has
been selected to be observed. Now it does.
Changed system to go over the LST indices

Now each cycle starts at the galactic plane (indices 17 and 78) and
the LST distribution is cycled symmetrically (first the SGC and then
the NGC)