Add completion for canto.
Fix canto completion

-d option was forgotten, causing error for last complete command
Avoid standard command not found message when command-not-found is found

Squashed commit of the following:

commit c208bc30b7747b3743212483b3dd7e3f90819f49
Merge: 97bea94 2633372
Author: Konrad Borowski <glitchmr@myopera.com>
Date:   Fri Jul 19 09:56:12 2013 +0200

    Merge branch 'command-not-found' of git://github.com/GlitchMr/fish-shell into command-not-found

commit 26333721b9048333d1e7932505c221a31fd0e624
Author: Konrad Borowski <glitchmr@myopera.com>
Date:   Fri Jul 19 09:55:13 2013 +0200

    Fix command_not_found when not found

commit db34460bb51a4b1c1c456c2e535ae8d913d1071e
Author: Konrad Borowski <glitchmr@myopera.com>
Date:   Wed Jul 17 13:41:57 2013 +0200

    Avoid showing standard command not found message when possible

    In bash, command-not-found handler causes the standard messages to
    not appear. Because of events model in fish, it isn't really an
    option, so I moved the standard command not found message to
    fish function. This way, the messages aren't repeated, and the
    standard command not found message appears only when handler
    couldn't be found.
Initial abbreviation work. Tests currently fail.
Next stab at abbreviations. Highlighting should work.