Update MANIFEST.in with simpler template commands

Please see https://docs.python.org/2/distutils/sourcedist.html#commands for reference.

MANIFEST.in

@@ -1,13 +1,11 @@
 include Makefile CHANGES LICENSE AUTHORS
-recursive-include artwork *
-recursive-include tests *
-recursive-include examples *
-recursive-include docs *
-recursive-exclude docs *.pyc
-recursive-exclude docs *.pyo
-recursive-exclude tests *.pyc
-recursive-exclude tests *.pyo
-recursive-exclude examples *.pyc
-recursive-exclude examples *.pyo
+
+graft artwork
+graft tests
+graft examples
+graft docs
+
+global-exclude *.py[co]
+
 prune docs/_build
 prune docs/_themes