Update Awesomium to 1.7.1

Fixes #390 

Screenshot:

Before: ![image](https://f.cloud.github.com/assets/359239/765743/a344ed28-e83a-11e2-8246-c208270e9981.png)
After: ![image](https://f.cloud.github.com/assets/359239/765788/0d539c80-e83d-11e2-91b9-cfa8f257b4e0.png)

TODO: 

- [ ] resolve black border alignment issue
- [ ] deal with any feedback raised on Win7/Win8