[Usability]gnome-terminal encoding UI

[Havoc Pennington <hp redhat com>]

Hi,

Traditionally terminal emulators for X let you set the encoding of the
stuff in the terminal as part of setting the font. The way things work 
with Pango/Xft2/fontconfig is that all fonts look like Unicode
fonts. So we need to know what encoding to convert from, landing in
Unicode.

Web browsers have the same problem (due to broken HTML not including
the encoding label). You can see the Mozilla UI for this under 
View->Character Coding.

Here is a possible gnome-terminal UI which is similar to Mozilla's but
a bit less complex (no autodetect, and no More submenu):

  http://pobox.com/~hp/terminal-encoding.png

I wanted to have some visible feedback about the current encoding, so
I tried this corny thing where the menu is titled according to the
current encoding and right-justified.

(Where it says Western it should say Current Locale, or vice versa, 
a bug in my current code.)

The "Add or Remove" dialog is used to change what's in the menu, since
otherwise the menu would be huge, and too annoying to use (most users
who use this feature will be frequently toggling between a couple of
encodings).

In addition to what's visible in the screenshot, there would be a
per-profile "default encoding" setting, used for new windows.

Havoc