[dev] [surf] key configuration (config.h) patch

Hello,

I recently discovered surf, and was attracted to the conciseness of
it's code. From the dev mailing list archives, I think I recall Gottox
(or someone) saying there was no plans to add a config.h way of
customising surf. And looking at the code [keypress()] I can see why,
it would add complexity to wrap webkit and gdk functions. But I think
customising key bindings through the source code would interfere with
people wanting to write and submit patches. I really want to see surf
improve, so I went ahead and added the config.h feature.

I modelled it after dwm, and I noticed for the feature to be flexible,
I had to modify the api of many functions to take in an Arg argument.
I didn't want to change the api, but I think it's a change in the
right direction. I didn't add Arg to every function, only the ones
specified in config.h, if Gottox merges this patch into the trunk,
I'll make changes to the remaining functions.

I wrote some wrappers to webkit and gdk calls. Also, I modified
load_uri() a little because I didn't want a wrapper that just loads
the url from bar and hides bar, also to demonstrate that "chaining"
commands is possible (see attached config.h).

The enum Keypressmode is sorta not pretty, but I used it to preserve
semantics of original keypress(). Also I was thinking it could be used
to add a modal feature (like vim or uzbl).

Thanks