fixed hhvm build.

show PHP extension version

also enhance test README

Used a single database and a single CLI entry point for all test types. Added faker to basic app dev requirements.

- Moved everything test-related into `tests` directory. Codeception tests are in `codeception`.
- Removed database module since we're using fixtures and migrations.
- Moved console entry points and bootstrap into `tests/codeception/bin`.
- Adjusted travis build scripts.
- Adjusted documentation to be consistent and reflect changes made.