Add logic to check if team coluors are light/dark

Chooses the correct text colour based on the team colour so the text
will be legible.

Before:
![light-colour-stats](https://f.cloud.github.com/assets/29761/2485482/93498e6c-b119-11e3-8ca7-c2a3d1a927fa.png)

After:
![fixedstatstextcolour](https://f.cloud.github.com/assets/29761/2485493/b4c9a9fa-b119-11e3-8483-47ac77994686.png)