Change the name of a spinner

Threshold spinner's name looks better this way and makes more sense
next to the others.
Add Clusterpy (Only maxp-algorithm) to the plugin

The clusterpy file contains the required methods and the max-p
algorithm.
* This is a long file. A near future enhancement will be to divide
the file into a directory with a few files with the minimum require
clusterpy functionality for the algorithms.
Remove trailing white spaces