All inputs implemented by translation to EA

Implementing direct parsers for the different "formats" is kind of
silly when, really, it's all just EA anyway. So stop doing that and
replace the EAV and tabular parsers with conversions to EA format.
Add test cases comparing the generated graphs
Add usage information to README
Rename tabular example file
Add example data for the planets
Test that translation maps filter duplicates

Also: update tests to use new file names for tabular data.
Example data description