fix a typo.

Rewritten testing introduction, added environment setup to README.md, removed empty pages that were not referenced

changed bootstrap namespace to jui

- 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.