Include tests, license, docs in source distributions

closes #475

MANIFEST.in

@@ -0,0 +1,12 @@
+include Makefile CHANGES LICENSE AUTHORS.md
+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
+prune docs/_build
+prune docs/_themes