Adjust manifest to include notebooks

Author: lmcinnes

MANIFEST.in

@@ -1,2 +1,4 @@
 include *.rst *.txt
-recursive-include hdbscan *.py *.pyx *.pxd *.c
+recursive-include hdbscan *.py *.pyx *.pxd *.c
+recursive-include notebooks *.ipynb *.npy *.svg
+recursive-include examples *.py