Revision creation button + Multi Database support

[Masadow]

This little update add a New revision button which create a new folder with an empty comments.sql file.

The new revision number is the highest revision number + 1.

The main goal of this is to create a new revision and add directly your SQL changescript into comments.sql without going out of the webapp.

Improvments can be make like the ability to choose revision number, manage multiple files creation and so on.

Also, support multi database by supporting multiple config file. You just have a select on the main page to choose your configuration.