Add note and link about SlicerTractParcellation

#12 (comment)

#11

Fixes #11

Author: pieper

README.md

@@ -1,5 +1,7 @@
 # SlicerWMA
 
+Note: this extension is being deprecated in favor of the new and improved [SlicerTractParcellation](https://github.com/SlicerDMRI/SlicerTractParcellation)!
+
 [![License](https://img.shields.io/badge/License-BSD-green.svg)](https://github.com/SlicerDMRI/SlicerWMA/blob/master/License.txt)
 
 This is a Slicer extension to provide access to Lauren O'Donnell's [whitematteranalysis](https://github.com/SlicerDMRI/whitematteranalysis) package.