This commit marks the first production release of Mentat system 2.0.0. After lots of work we have finally successfully abandoned the original implementation written in Perl and using MongoDB as database backend.

This commit also marks the end of an era of frantic coding. Until now some of the guidelines and best practices for coding and committing were violated in favor of faster development. This was also possible thanks to the fact that there was mostly only single developer working on the project, so there were no possible conflicts. From now on however things will be back to normal state.

(Redmine issue: #3387)