Mod support extended

Preparing for RU 2.1.0.0

Adds mods requested by the community and those showing up in RR.
Documentation update

The version number for Archimedes' Ships has been corrected at the same time as it being updated; the correct previous version was v1.3.6.

Dave can get GasCraft to run in testing but I can't. The config is supplied anyway.
Updated changelog

We're good to go! :)
Merge pull request #11 from velotican/patch

RU 2.1.0.0