Merge pull request #3 from psteinhoff/image_processing

Image processing
added the test_alex_lowpass_3 - it fails as by now
Merge branch 'psteinhoff_image_processing' into image_processing
added copy_images to make sure boundaries are original in alex_lowpass_3
added test that passes now
added test_histogram that passes
changed filter_3 to be compatible with alex_lowpass_3
added simplest test without filter.par file that passes, TODO: create filter.par test various options from Patrik
Merge pull request #7 from alexlib/image_processing

alex_lowpass_3