hex unicode input

[Matthias Clasen <mclasen redhat com>]

I have just committed a patch to GTK+ head which redoes the
hex unicode input feature.  Here is the description from the 
ChangeLog:

2005-09-02  Matthias Clasen  <mclasen redhat com>

	* gtk/gtkimcontextsimple.c: Rework the Unicode hex input
	code. Now we only steal a single key combination, Ctrl-Shift-U,
	instead of sixteen. 
	A hex Unicode sequence must be started with Ctrl-Shift-U, 
        followed by a sequence of hex digits entered with Ctrl-Shift
        still held. Releasing one of the modifiers or pressing space
        while the modifiers are still held commits the character. It is
        possible to erase digits using backspace.
	As an extension to the above, we also allow to start the 
        sequence with Ctrl-Shift-U, then release the modifiers before
        typing any digits, and enter the digits without modifiers.
	(#82011, Owen Taylor)

Since this is some hairy code (while working on it I found several
bugs in the old implementation), I'd appreciate if people could try
it out. I hope that stealing Ctrl-Shift-U is not a problem for many
applications. At least they get the sixteen valuable
Ctrl-Shift-<hex digit> key combinations in return !


Regards, Matthias