comboboxtext and comboboxentry searching

[GoogleCodeExporter]

comboboxtext and comboboxentry searching.

Implemented in code and activated via a custom tag atttribute.

comboboxtext:
User presses a key, the next item that begins with that case insensitive char 
is selected and it'll wrap back to the first.

comboboxentry:
It can't be search-as-you-type because then the user would be trying to type 
something into the entry and the code would be attempting to set it to an item 
in the list, so the search code must be activated on Enter and it'll have to be 
done on the "activate" signal before the signal reaches the application. This 
could of course interfere with an <action signal="activate"> so the application 
developer is not going to want to use the both together.

Original issue reported on code.google.com by [email protected] on 14 Oct 2011 at 10:32