OpenSans & Inconsolata

The modest changes in this proposal switch the default typography from Lucida-Grande & Menlo to OpenSans & Inconsolata. This should provide a more consistent onscreen appearance on a variety of operating systems because OpenSans & Inconsolata are both included in the application as `woff` files. Hopefully it will also reduce the number of issues that pop up relating to text fit and placement onscreen (for example: #64, #99).

Here are some screenshots of the revised treatment:

![image](https://cloud.githubusercontent.com/assets/8218578/3841298/ff0b5d2e-1e29-11e4-872a-a38afc56d178.png)

![image](https://cloud.githubusercontent.com/assets/8218578/3841303/0f563730-1e2a-11e4-92b1-19db07f3c1c6.png)

![image](https://cloud.githubusercontent.com/assets/8218578/3841329/7d53eea8-1e2a-11e4-90ff-4326892e20cb.png)

![image](https://cloud.githubusercontent.com/assets/8218578/3841336/a8919e30-1e2a-11e4-85a0-eb70c98543cc.png)

![image](https://cloud.githubusercontent.com/assets/8218578/3841330/8a80d2e4-1e2a-11e4-8602-c166842f6d49.png)

![image](https://cloud.githubusercontent.com/assets/8218578/3841333/99d19882-1e2a-11e4-8676-5eea880ad274.png)