Figure out path to upstreaming changes

The quality of some of the customizations has increased beyond ugly hacks, we should be able to upstream at least a small subset of them.

• propose to change license for CSS files to the same that upstream FF uses (Mozilla Public License v. 2.0) - get everybody on board, right now there are not that many contributors in the tree (#31 (closed))
• upstream a simple change that makes one of the about pages more adaptive to FF to get a hang of the workflow
• document the workflow
• make a list of what can/should be upstreamed and start working on that