core.edi: redefined "station" attribute....allows to set attribute incl. update of edi.head[dataid] entry

Signed-off-by: LK <LK@uni>
core.edi: corrected underscore tippererr in data_dict method

Signed-off-by: LK <LK@uni>
core/edi.py: added dummy values for lat/lon/elev in the head section - cleaned up the lat/lon/elev methods

Signed-off-by: LK <LK@uni>