Remove usage of deprecated gtk+ objects about mupen64plus HOT 7 CLOSED

Here is a quick patch to replace the custom directory browser (dirbrowser.c/h) 
with
the standard GTK+ one.

Thanks for the contribution! I'd already made a similar change in r153. Make 
sure you
checkout the latest svn revision before making changes. See the project 
homepage for
instructions on how to checkout the latest svn revision.

Oh right ! I was still using the old svn repository
(svn://fascination.homelinux.net:7684/mupen64-amd64/trunk) instead of the new 
one
(svn://fascination.homelinux.net:7684/mupen64plus/trunk). This new version is a 
lot
better !

How is this coming along?

dirbrowser.c was removed awhile back with r153. romproperties.c no longer uses 
any 
depreciated widgets but the dialogue itself needs some more work as the 
calculate 
MD5 button is a no-op, see Issue 66. vcrcomp_dialog.c is never sourced as the 
VCR 
subsystem (not to be confused with fast-forward) has its own issues. 

Might be best to close this Issue and start another for VCR support. 

We have an issue for ReRecording which is basically a VCR ticket.

I agree that we can consider this issue fixed, even though the GtkCombo in the 
VCR
code is not yet fixed. We'll update it as part of getting VCR support to work in
general. Nice job everyone.