Add new themes to Preferences->Appearance dialog

Added neon.css and existing (but unused) .css themes to AceThemes.java
and AceThemesResources.java, changed size of Preferences dialog box to
accomodate extended theme list.
![Screen Shot 2013-02-05 at 11 57 37 AM](https://f.cloud.github.com/assets/1776358/128311/56d8f0ea-6fb5-11e2-8b16-c00fa58a7c99.png)