Discussion changes

Changes
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- Various discussion style / layout changes (see screenshot)
- Fixed recommend binding multiple times
- Fixed recommend not working for replies that were truncated
- Fixed multiple comment boxes appearing when clicking a reply button more than once
- Show reply button when not signed in and link to signin page

Before
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![image](https://cloud.githubusercontent.com/assets/960919/4504683/c77d2274-4ae9-11e4-9cdf-0b89602eaea4.png)

After
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![image](https://cloud.githubusercontent.com/assets/960919/4504685/de0c19e6-4ae9-11e4-8f85-f52fbcb96377.png)

It should be added all at once I agree. There is a lot wrong with our comments code at the moment, including feature breaking bugs, but we only have limited time to put fixes in so I'm going to leave this as is for now as it is still an improvement over what's currently in production.