implemented support for cloud masks / bad data masks

components.CoReg.imParams:
- __init__():  added attribute mask_baddata
- added add_mask_bad_data()

components.CoReg.COREG:
- __init__(): implemented new keywords 'mask_baddata_ref' and 'mask_baddata_tgt'
- _get_opt_winpos_winsize(): now checks bad data mask if window position is within bad data area

components.CoReg_local.COREG_LOCAL:
- __init__(): implemented new keywords 'mask_baddata_ref' and 'mask_baddata_tgt'

components.Geom_Quality_Grid.Geom_Quality_Grid:
- get_CoRegPoints_table(): added vectorized filtering of points within bad data area
- _flag_outliers(): added docstring, some minor revisions

coreg_cmd:
- renamed parameters path_im0 and path_im1 to path_ref and path_tgt
- added parameters '-mask_ref' and '-mask_tgt' to global an local argument parser

- updated __version__