[Gitweb-caching][RFC] Major updates - kernel.org updated

Evening everyone,

Thought I'd give a heads up that I finally sat down and did some major updates to my version of the gitweb caching code (as opposed to Lea's, which I still have plans to integrate with mine in the near future).

That said this brings the base up to mainline, which is about a 2 or 3 
year jump in code, it updates a number of elements in the caching engine 
  itself and I went ahead and ripped out the file breakout that I had 
done initially.

New things known to work:
	- Snapshots are fully working, and passing through the caching
	  engine
	- Binary files now output correctly when your using blob_plain,
	  this is also passing correctly through the caching engine.

I'm sure there is a plethora of other things that have been fixed or broken.

So I'm going to re-open the can of worms over caching again, and see what it would take to get this merged into mainline. Obviously a patch clean-up (my tree is a lot more organic than mainline) is needed, but I thought I'd try and get an idea of where I need to start steering all of this.

- John 'Warthog9' Hawley