Add VERSION and README.rst to MANIFEST.in to fix pypi installations.

NOTE: I did not update the sphynix docs.
Remove test/__init__.py

Turns out we don't want the test package to be a real package as it
collides with the standard library.
Strip the VERSION file when reading.

VERSION is generated by the Makefile normally but I didn't want
to taint my tree by running the make target but did want to set
the VERSION manually for testing purposes, where my editor insists
on leaving a trailing newline.  This just makes sure the VERSION
is imported correctly regardless of local edits or being genrated.