Implementation of missing parts of VOOT connector

In this pull request I forward an update to the VOOT connector that, in respect to the previous implementation:
- implements all the API endpoints of the VOOT protocol
- implements the management of additional parameters (like search, startIndex, count, sortBy)
- reviews code style, comments and some package name.

This development is still under-tested (since no JUnit has yet been created for it) however has been humanly tested on an existing Grouper 2.2.0 instance.