Refactoring galore!

- Unify interface between Alert, Deployment and Client
- Move app_key to Client
- Add a send() method to Deployment
- Add a status parameter to both deployment and alert
- client parameter is now optional for alert and deployment
Typos and bugfixes
Update docs and some methods
Use simplejson when possible
Add gitignore
Bump version
Merge branch 'release/2.0'