Updates icons in discussion show page

Created two new buttons based on the current ones available.
Removed unused code.
Removes comments module, there was already a comment directive on the components folder. We don't know yet if a module is required.

![screen shot 2014-12-29 at 16 01 39](https://cloud.githubusercontent.com/assets/934580/5570098/0af8046e-8f74-11e4-82c1-5925527af395.png)