adding attachment flags to the flag labeling.

with this change we'll be able to see bug flags and attachment flags labeled in the bug summary fields.  this gives us a more complete at-a-glance status picture of each bug.  this pull request includes test data and unit tests to verify the attachment api support.

![attchment_flag_labeling_1](https://f.cloud.github.com/assets/5017470/1518100/029ee76c-4b30-11e3-916e-6e44ae8e7602.png)
![attchment_flag_labeling_2](https://f.cloud.github.com/assets/5017470/1518101/02d30a1a-4b30-11e3-92ac-7c4e220f3db0.png)