tglc v0.6.5

1. Changed the naming behavior of setting first_sector_only=True or last_sector_only=True in tglc_lc(). Now the source_cut pickle file will be named by actual sector number instead of only saying 'first_sector' or 'last_sector'.
2. Revamped the quick_lc.plot_contamination() function. It can now be used to qualitatively compare pixel light curves of each target to distinguish which star is responsible for a certain variability.