Enhancement: import xorg compose sequences

[GoogleCodeExporter]

xorg has a well sorted list of compose sequences.
http://www.x.org/releases/X11R7.6/doc/libX11/Compose/en_US.UTF-8.html

I am planning to write a conversion tool which translates entries from xorg 
into the scancodes of the locally installed keyboard.

Advantages: you can search the definition file with a text editor.
The compose sequence would be the same for different (latin) keyboards.
Currently, the default compose sequence for ń is n + apostrophe on an US 
english keyboard. It becomes n + ä on a german keyboard, which is more 
difficult to remember.

For the wiki: extract small lists of compose sequences per language.
Which sequences are required for a given language? For german, you need 7 
non-ascii characters: ä ö ü Ä Ö Ü ß.

Original issue reported on code.google.com by zus...@gmail.com on 10 Jul 2014 at 6:58