This is a big big GTK file dialog change in Rambetter-temp-fixes branch.

This is	a big big GTK file dialog change in Rambetter-temp-fixes branch.
Thank you to Markus Fischer who	provided some example code on how to
use the	"new" method of	GTK file dialogs.  I then did a	lot of research	into
how to shape his code into exactly what	I wanted.

This is	an incomplete change in	that I have not	cleaned	up the code such
as removing unused local variables and unused functions	yet.  However, I
wanted to commit this now because it really works beautifully (the GTK file
dialog that is).

- In CFileType,	m_pstrGTKMasks now contains string like
"quake3 maps (*.map)" instead of like "quake3 maps <*.map>".  Nobody else
is using this code except in gtkmisc.cpp so it's a safe	change.

- Removing all FILEDLG_DBG blocks in gtkmisc.cpp.  It really clutters up the
code and since it's completely overhauled, it's	OK to remove.

- Instead of the "old" way of gtk_file_selection_new(),	now using
gtk_file_chooser_dialog_new() instead. 	Thx to Markus Fischer for examples.

- Actually adding GTK file dialog filters.  It works really nice!  :-)

- Now using the	same file extension logic on Windows file dialogs and GTK
file dialogs.

- Improved file	extension logic.  "No file extension specified in file to
be saved.  Attempt to save anyways?"

Tested on Win7 and Linux.
More related changes on the way.

THIS SHOULD BE MERGED INTO TRUNK.

git-svn-id: https://zerowing.idsoftware.com/svn/radiant/GtkRadiant/branches/Rambetter-temp-fixes@355 8a3a26a2-13c4-0310-b231-cf6edde360e5