(Refactor branch) Made use of the language system wherever possible

_This is for the **refactor** branch._

An even bigger pull request this time (666 additions and 405 deletions).

I combed through _every_ DarkRP file and made use of the language system wherever possible. I hopefully didn't miss anything! Things I haven't touched however are:

* FAdmin and FPP
* 'f4menu' module. You're recoding this soon.
* The animation buttons. They are awkwardly defined right when the file was included. They have since moved to modules however after starting work on this last night so I've not checked what the case is now (don't worry, I have merged all the upstream changes so you don't have conflicts to deal with).
* Errors. People who are interested in this are scripters and scripters will most likely speak English.
* Logging. Similar reason to above.