Simplifying grammar dramatically. Using proper types to create more predictable and consistent JSON outputs.

Removes /gui endpoint. The gui is now presented at /.
Adds /parse endpoint. This endoints receives /'s former functionality.
Adapted README to reflect the new URLs.

Using port 80 for docker-compose service, reordering Dockerfile for faster rebuilds at the cost of an additionaly RUN.

The development server uses docker-compose run and mounts the
app directory. It then runs the flask development server.
The production server uses docker-compose up and runs flask as a
uwsgi app behind nginx. It does not mount app.

Additionally, the grammar now uses custom semantics and creates flat
structures.

For example, the sentence 'take the cup off the table and bring it to
the shelf' has six different parses, four labeled with 'smain', and two
labeled with 'smain/.r'. Previously, since the labels were used for the
dictionary keys, only two parses were returned (and the others
overwritten).
Now, the parses are labeled as smain, smain/0, smain/.r, smain/.r/0,
etc. to provide unique keys.