Laid traces on pcb. Added .gitignore.

Added .gitignore which now ignores the cache libraries and bak files, and the directory I'm using for screenshots.

Here's the change in this commit for the pcb. I laid traces for a single-sided layout.
![screenshot](https://cloud.githubusercontent.com/assets/1036922/3635864/802ea294-0f8e-11e4-80a9-74dbeeca9232.png)