Implemented standard usage of the pretty variable printing class

- Added Debug Bar Pretty Print as a submodule to this repo -> Always pull update the submodule before releasing a new version from now on!
- Leveraged use of the Pretty Print class with filters for the explanation column (means that if people would have out of date debug bar plugins (from before now) and would happen to load the old Pretty Print version first, the explanation column will not be shown. Still, as we're talking developers and these plugins are essential tool for them, I expect that this will rarely happen.

Release ready version:
- Upped the version number
- Updated translation files
- Renewed screen shot to reflext the new look
Updated submodule
Mini-CSS fix
Code style sniff
Empty index.php files for directories
Merge pull request #3 from jrfnl/master

Implemented standard usage of the pretty variable printing class