adding local_maxmin on 5*5 points, and 3D Savitzky Golay at the 4th
order on a 5*5 patch
work ongoing
Merge remote-tracking branch 'upstream/master'

Conflicts:
	pyFAI-src/blob_detection.py
bring back changes from discared branch
Merge remote branch 'aurore/master'
work in progress on the peak-picking side.