Modifications to original acme:
 - Alternative chording with the mouse wheel instead of B2 and B3.
 - Interprets '|' with B2+B1 chords as the Edit command.
   (see http://9fans.net/archive/2009/08/571)
 - B3 on a path only completes until the next / (allows to open parent directories with a single click).
 - Better auto-menu for files and directories.
   (see http://9fans.net/archive/2009/03/229)
 - Column mouse actions:
    - B1: increase size
    - B2: maximize size
    - B3: move to left-most position and hide the other clients
   (see http://4l77.com/pub/acme-growcol.mpeg)