Hide overflow in last post column.

If the text did not fit in the last post column, it overflowed into the row below it. I'm not sure what the most aesthetic fix is here but this seems reasonable.

Before:

![screen shot 2014-04-08 at 6 40 48 pm](https://cloud.githubusercontent.com/assets/842035/2650284/84917a2e-bf6f-11e3-87cc-028b527f6c0c.png)

After:

![screen shot 2014-04-08 at 6 40 58 pm](https://cloud.githubusercontent.com/assets/842035/2650285/89acb96a-bf6f-11e3-8f6c-ee4fa06cb5c3.png)