Documentation updated

Thanks to the great job by Neil Caldwell, Tagaini now has an up-to-date and extensive user manual, which will be integrated into future releases.

Neil did not stop there since he also turned the previous documentation into a quick start guide and also wrote an extensive installation manual with details about how to configure your system properly in order to enjoy Tagaini. Hopefully all these nice documents will be updated and further improved as new versions are released.

Thanks, Neil!