fixed Makefile setup to run tests

Also changed `champtests` to `champ_dev` so
`champ` can be a "production" db and one can
`champ_dev` along side.
ignoring node_modules
removed included Mutagen because GPL; added README

This is for the `tag.py` tool shipped alongside
champ which may become the basis for a (mostly?)
implemented `index` command.