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

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

- updated __version__ and __versionalias__

geo.raster
- __init__.py: added __all__
- added module conversion containing new function raster2polygon for polygonizing raster arrays

io.raster:
- gdal:
    - get_GDAL_ds_inmem(): gt and prj are now optional keywords
- GeoArray:
    - added function _alias_property()
    - GeoArray:
        - added attribute basename
        - __init__(): added FileNotFoundError for Python 3
        - added 'nodata' property that return nodata value
        - refactored cols attribute to 'columns'
        - added alias attributes 'cols', 'gt', 'prj'
        - added 'mask_nodata' property that returns a no data mask (uint8)
        - added 'footprint_poly' property that returns a shapely polygon with the corresponding footprint
        - added nodata value derival to set_gdalDataset_meta()
        - save(): added automatic creation of output directory
        - _get_plottable_image(): now respects nodata value
        - show(): now respects nodata value
        - show_map(): now respects nodata value
        - added show_footprint() function that shows a zoomable map containing the footprint polygon as overlay (Jupyter Notebook internal)

io.temp_io => refactored to 'pathgen':
- added function get_generic_outpath()

numeric.array:
- added function find_noDataVal() to derive nodata value from a given numpy array

ptds.__init__:
- updated __version__