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 *
+graft artwork
-recursive-include examples *
+graft tests
-recursive-include docs *
+graft examples
-recursive-exclude docs *.pyc
+graft docs
-recursive-exclude docs *.pyo
+
-recursive-exclude tests *.pyc
+global-exclude *.py[co]
-recursive-exclude tests *.pyo
+
-recursive-exclude examples *.pyc
-recursive-exclude examples *.pyo
 prune docs/_build
 prune docs/_themes