Support for lon/lat -based area extents.
Test for mpop.satin.mipp_xrit.lonlat_to_geo_extent()
Helper functions for area extent and bondary calculations, and data reducing for swath data.
Added area extent calculations based on given area definition names.
Added possibility to do data reduction based on target area definition names
Reverted not to reduce swath data
Removed swath reduction functions
Removed unnecessary functions
Test for area_def_names_to_extent()
Removed unneeded functions
Merge remote-tracking branch 'upstream/pre-master' into pre-master

Conflicts:
	mpop/satin/aapp1b.py
Moved to mpop/tests/
Moved to mpop/tests/
Added tests for mpop.satin.helper_functions
Fixed import
Possibility to give also area definition objects to area_def_names_to_extent() and log a warning if the area definition is not used
Test using area definitions instead of definition names
Fixed incorrect correct values
Re-ordered the tests
Added test if proj string is in + -format or not