Add lesson: atmanepada
Add tool: meter recognizer

This is the very first version. It's pretty crude.
Rename various assets to saner things

Mainly the templates and static assets in 'tools' and 'dicts'
Add syllable display in meter recognizer
Refactor tools CSS and add CSS for syllables

Goal: unify CSS common to all tools in a single file. Currently each
tool just imports the base file, but in the future they should probably
do something smarter.
Add line-by-line support in meter recognizer
Add multiple-block support in meter recognizer
Fix incompatibility problems with dependencies

This is the first commit in quite some time, and a lot of things are
broken.

Currently: I can bring up the site, but the site goes 500 on a database
error. The database can't be built because fabric can't be loaded.
fabric can't be loaded because of context issues with Flask.

Revival plan:

1) Clean until the site can be loaded.
2) Clean until the site can be build with a single command (or two).
3) Add saner packaging for 'sanskrit' package
4) Automatic linting
5) Unit tests for all non-trivial pieces of code