Lkml

- Fixed an issue with `bind_filters` plural keys (30)

- Fixed an issue with `sql_where` plural keys (25)
- Added support for LookML data tests (28)

- LookML serialization (generation) from Python objects (14)
- Load LookML from string as well as from a file object (17)
- Added local test suite via Docker (jamescurtin)
- Added docstrings and examples throughout codebase (16, jamescurtin)
- README updates on LookML representation
- Add `CONTRIBUTING.md` guidelines including details on running test suite

- Remove some unnecessary imports
- Pluralize keys for `action` and child fields (12)
- A few small changes to `setup.py`
- Stop lexing dimensions starting with `sql` or `html` as expression blocks (11)

- Allows hanging commas in lists
- Allows duplicate top-level keys but warns that they will be overwritten
- Logging shows the log level to differentiate between `DEBUG` and `WARNING` messages
- Remove portion of `SyntaxError` message which points to a non-existent line position
- Collapses multiple `sql_step` and `sql_where` keys into plural keys
- Some metadata fixes to `setup.py`

- Improved syntax error handling to display the line number of the error
- Reached 100% test coverage
- Moved CLI and argparse functionality into independent functions
- Some small performance optimizations
- Better debug logging, only when debug flag is specified