The lisp client now passes the prefix to the C server so filtering can be done in C before writing completions to std output. Also, define a miximum number of completions to be printed.
Get rid of ac-clang-saved-prefix.
Sort completion results in C by clang's priority heuristic, rather than alphabetically.
fixed invalid reference to image
Merge remote-tracking branch 'refs/remotes/upstream/master'
Applied the patch committed by cjacker (make clang_complete only one instance).
Merge remote-tracking branch 'refs/remotes/upstream/test'

And do some random clean-up.
The whole thing is a mess. :(

Conflicts:
	auto-complete-clang-async.el
Minor random clean-up.

I should learn how to use git, too.
Remove unused function.