Few discussion/profile tidy up bits

* Add comment activity to ID nav items
* Make replies the right colour
* Add permalink to date

# Believe it
![activitylink](https://cloud.githubusercontent.com/assets/31692/3130238/52ad762c-e7f4-11e3-8e2c-1bb97b2eff9d.png)
![replydark](https://cloud.githubusercontent.com/assets/31692/3130240/52ae83be-e7f4-11e3-9ae0-c093784e02e7.png)
![permalink](https://cloud.githubusercontent.com/assets/31692/3130239/52adcffa-e7f4-11e3-8897-1e606e10d7fa.png)