Added new traits tab to Ship Basic Stats window

I've added a traits tab to the Ship Basic stats window so that users can see what bonuses ships have.
Example:
![image](https://f.cloud.github.com/assets/1392544/2105551/7e09955c-8f8f-11e3-8858-8fc1220984a0.png)

This required adding a new table, invtraits, to eve.db as well as a few tweaks to the item.py, types.py and itemStats.py files. I added a new class, Traits, to represent the traits an item can have.