Integrate docs(wiki) into source repo

[NaN]

Anyone interested in this?

The motivation is to make it easier to keep the docs in sync with a release and project changes in general, be able to include docs into release builds.

From what I see it should also be possible to view the docs directly on github when sticking with Markdown(.md) file format (need to test this), replace current wiki.

The task would be to add a docs dir and copy wiki page sources into it, fix up relative links where required.