Show actual commit count on project dashboard

## What does this MR do?
Instead of displaying the rounded commit count this shows the actual commit count on the project dashboard. Also added the number_with_delimiter helper to show the numbers in a nice, human-readable format.

## Why was this MR needed?
The rounded commit count is great for a quick display of the commits, such as for the public project list. However, for the dashboard it is overly simplified. When a project has between 1,000 and 5,000 commits you just see '1000+ commits'. There is no reason we shouldn't show the complete commit count here.

## Screenshots

Before:
![screen shot 2014-04-14 at 11 27 02 am](https://cloud.githubusercontent.com/assets/2394772/2697726/af1a0b86-c3f1-11e3-924f-b17d7838f448.png)

After:
![screen shot 2014-04-14 at 11 59 08 am](https://cloud.githubusercontent.com/assets/2394772/2698112/23949cd4-c3f6-11e3-9592-086c875ba494.png)