Move Import Library.. to file menu, Minor fixes in FunctionNamePrompt

### Fixes

The Libraries menu is brought too high up in the interface, even though I reckon it is a fairly seldomly used feature.  It confuses users with Packages, too.  I've moved it into the file menu where it is a bit less confusing for first time users.

The FunctionNamePrompt had some minor issues.  The gradient looked odd and the placeholder text was incorrectly placed and of the wrong font size.  It's fixed now.  It also did not come up centered on the window.  This is annoying and now fixed.

### Screenshots

![centered](https://cloud.githubusercontent.com/assets/916345/4923691/c1933ef0-651c-11e4-9558-d8f3cb7b2186.PNG)

![importlibrary](https://cloud.githubusercontent.com/assets/916345/4923692/c19599a2-651c-11e4-9aad-fac2642ff03b.PNG)


### Reviewers

@ikeough