Markdownify: render markdown into html

Added to description of projects in the list and the item-view as well as to the content per step. Examples as one can see. 

![bildschirmfoto 2013-07-16 um 23 42 18](https://f.cloud.github.com/assets/40496/808573/dc956756-ee66-11e2-9bb3-1e26bfbf3a9e.png)
![bildschirmfoto 2013-07-16 um 23 42 27](https://f.cloud.github.com/assets/40496/808575/e17dbba6-ee66-11e2-9953-9bf8d957b61a.png)


It is based on the redcarpet plugin and as such requires to rerun 'bundle' after merging in order to install it. Happy hacking.