Make rnc2rng more CI friendly

The script now becomes useful as: SCEMAS_PATH=<path> scripts/rnc2rng.sh to
compile all schemas in SCHEMAS_PATH or you can compile one schema with
scipts/rnc2rng.sh <src> <dst>
Make rnc2rng more CI friendly

The script now becomes useful as: SCEMAS_PATH=<path> scripts/rnc2rng.sh to
compile all schemas in SCHEMAS_PATH or you can compile one schema with
scipts/rnc2rng.sh <src> <dst>
Cleanup file structure and remove non-needed Makefiles

Makefiles are deprecated functionality, make test for example with tox.

MANIFEST.in provides info for packaging.
Use tox and testrepository for tests

Using tox for tests means you can run tests against all versions of python with
1 command.

Also when running "tox" you gain the ability to run syntax checks using flake8
on the code at the same time.

tox also installs each env in a different virtualenv so it is isolated from
your main dev env.
Remove __main__ code from tests
Merge pull request #8 from ekarlso/tox-for-tests

Tox for tests