Git upload for advas-0.2.3 to advas-0.2.5 (beta)

The git module is enabled, and the source code can be retrieved from there, too. As the first steps the older advas version 0.2.3 was added as well as the unreleased 0.2.4, and the current source code for 0.2.5.

In contrast to the earlier releases, version 0.2.5 comes as an OOP class. This simplifies the usage. Currently, the German version of the documentation is nearly complete, the English version is adapted and expected to be finished within the next week.