rounded corners for chapter box (and a little extra)


![screen shot 2013-05-28 at 02 36 16](https://f.cloud.github.com/assets/657222/570134/cdd69582-c72e-11e2-977f-a958b5546fe3.png)

To make this work in Firefox the chapter table can not have its borders
collapsed and rows can not have background set.

* All backround rules for rows applied to cells instead.
* Replaced ```border-collapse``` with ```border-spacing:0;```.
* Minor CSS enhancements and cleanup

.gitignore

* ignore IDEA IDE settings folder
* Removed unnecessary asterisk in front of ```.DS_Store``` and
```Thumbs.db```