Fixed a bug which causes COREG.equalize_pixGrids() to run although the pixel grids of reference and target image are equal. Fixed ResourceWarning in COREG.show_matchWin() as well as in COREG.calculate_spatial_shifts(). Fixed exception in COREG.view_CoRegPoints_folium() in case of a recent version of folium.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>