Findpeaks

* fix for detection of valleys again
* fix for lee_sigma for parallel job
* catch error for plot persistence if not exist
* set the default limit back to None
* Fix for issue 27

This version can change the detection of peaks/valleys slightly in comparison to previous versions because it contains improved peak/valley detection fixes and some bug fixes.

* Fixing bug when peaks are identical in height when using 2D array data.
* Created some new functionality in plot that allows scattering the results on top of the image

* added parameter delta to params for flexibility



from findpeaks import findpeaks
fp = findpeaks(method='peakdetect', params={'delta': 1})

* Fix for caerus method cu parameter

* update setup file with joblib

* add limit as parameter for plotting