SBT multi-project setup

Changes:
- Upgrade API version to 16 (#43)
- Initial 'support-v4' wrapping
- Improved listener extraction: Now we have `searchView.onSearchClick` instead of just `searchView.onClick`.
- Removed `scaloid:generate` dependency from compile task, so we can try fixing and recompiling generated code without regenerating whole code. `;scaloid:generate;compile` does the previous behavior.

Known issues
- Android class extraction should run only once
- Insufficient v4 support