Implemented test flags like -Dtest.single to specify an include pattern of test files.

- Renamed some variable names to follow code standard
- Use Groovy accessors instead of Java accessors
Add documentation for new flags.

- Fix some typos.
Updated example to build tools 19, Android SDK 19 and latest Robolectric
Merge pull request #4 from SuperJugy/test

Implement test flags to specify an include pattern