[Mod] mushrooms [riesenpilz]

This mod adds mushrooms to minetest. The growing tool can make them giant.

**Depends:** see [depends.txt](https://raw.githubusercontent.com/HybridDog/riesenpilz/master/depends.txt)<br/>
**License:** see [LICENSE.txt](https://raw.githubusercontent.com/HybridDog/riesenpilz/master/LICENSE.txt)<br/>
**Download:** [zip](https://github.com/HybridDog/riesenpilz/archive/master.zip), [tar.gz](https://github.com/HybridDog/riesenpilz/archive/master.tar.gz)<br/>

![I'm a screenshot!](https://cloud.githubusercontent.com/assets/3192173/5332059/421c735a-7e47-11e4-88cc-b9ed90b659a8.png)

If you got ideas or found bugs, please tell them to me.


TODO:
* Mapgen: Do not use a fixed table of tree nodes; instead use a more flexible
  way to remove trees.
* Add a settingtypes.txt
* Make the growingtool craftable
* Test if visual_scale is useful for the small mushroom nodes,
  e.g. to make textures smaller or to use power-of-two sized textures.
  Nodeboxes would need to be changed accordingly (maybe automatically).
* Add new features:
  * Add more giant mushrooms
  * Add more content from the mushrooms mod
  * Add a lava suit