Provide full support for projections other than UTM or geographic coordinates.

This adds support for any projection of the input images.

Closes #37 (closed). Closes https://github.com/GFZ/arosics/issues/3. Relates to geoarray!24 (merged).

Tasks to be solved:

• release new GeoArray version which does not set GeoArray.projection to '' in case the projection is not EPSG compatible
• pin arosics to that GeoArray version
• fix COREG_LOCAL.view_CoRegPoints() by making GeoArray.show_map() compatible with non-EPSG datasets
• validate coregistration results
• add tests that cover non-EPSG projections
• update documentation