Add yummly.metadata() function for fetching Yummly metadata.
Increase wait time between tests. Seems to result in fewer timeouts.

Possibly due to less throttling on Yummly's end?
Rename `_version.py` `VERSION`.
Create Yummly models for API data returns.
Move yummly API access code to `client.py` and implement as a class.
Add __init__.py for tests module.
Update and simplify tests due to yummly.client yummly.models implementations.
Change `==` to `>=` for required dependency packages.
Update README with changes.
Add changelog files.
Add rst version of README.
Add manifest file.
Move `tests/` folder into `yummly/`.
Add `version.py` to `yummly/` and update version reference in __init__.py.
Update setup.py with new properties and prepare for version 0.3.0 release.
Add simple build scripts for converting markdown files to rst and updating VERSION file with `yummly/version.py`.