adds obsidian ore skin
Merge pull request #9 from jojoa1997/master

adds obsidian ore skin
Removed Thumbs.db (added again by Jojoa1997) and apdated skin credits.
Performed maintenance for ShadowNinja

* Added .gitignore
* Added compatibility with the IRC plugin

In the process, one minetest.conf setting was renamed, and another removed altogether. Other than that, 0gb.us_game should behave exactly as before.
Merge branch 'master' of https://github.com/0gb-us/0gb.us_game