Replace hyperglot

[moyogo]

• scripts/lang.py is not needed, or belongs in https://github.com/googlefonts/lang.
• Replacing hyperglot.parse and removing the dependency, fixes #498. The logic should probably be in a function in https://github.com/googlefonts/lang itself, or shaperglot to should be used instead.

[simoncozens]

Thanks for this. I think I would prefer to first move that logic to parse bases into gflanguages; gflanguages should be responsible for turning its own protobuf data into something more Python-friendly. Then the new method can be used here and in shaperglot.