Disable email notifications in Travis
These shouldn't be here!
Move sources into`src/main/java', update targetApi to 19
Fix some lint checks
Use style references correctly
Add Tests!

Includes:
- Initial setup for tests.
- Update the description.
- Add Travis status badge to README.
- Validate the maximum value. Make sure it's not below zero.
- Update some plugins, remove unused support library version

NOTE: Remember to set the working directory in IntelliJ to the library module
(not the parent) to run unit test from the IDE.
Update gitignore, remove weird manifest folder and delete screenshot.
Merge pull request #20 from f2prateek/tests

Add Tests