Refactoring, RSA Wrapper, and so on.

- Removed `ursa` dependency. It still work with `ursa` by default, need to add few lines about into doc's.
- Created rsa-wrapper via execFile with realtime cleanup.
- Added params for RSA wrapper.
- Auth method now works async.
- Updated tests.

It works on v0.11.x and still fast. Anyway look into.