Update all Glade files to GTK 2.24

And re-save them so that we hopefully get the new ordering of widgets,
preserved across saves.
Gray out compile buttons while compiling

The Go, Replay, etc. actions are all disabled while compilation is going
on.
Refactor compiling process to show results at end

Instead of loading the results page for each stage of the compilation,
show it at the end. This makes the code shorter and also removes the
need to wait for the GDK lock a few times during compilation.
Fix caching problem

On at least one version of WebKit (2.0.4-1.fc19) the Problems.html page
is cached and so does not get reloaded properly when the compiler writes
a new version of it. To be re-tested when porting to WebKit2.
Fix phony target

Since the target is not named after a file, it should be marked .PHONY
Refactor setting custom icon on folder

For clarity, refactor this into a separate function in file.c.