Soften up some of the UI elements.

A few tweaks to font sizes, weights, and colors to make the UI look less Gingerbread-ish. Also makes the touch targets for the items in the hamburger menu a little taller, so they are easier to touch.

These changes can be previewed here:

http://imgur.com/qwtBzlm
http://imgur.com/yZmH7ZQ

Those are images from the Android Studio UI editor, because I don't know how to build for Android yet.