Add growl error convenience methods
Add growl error convenience methods

CATMAID.msg(title, msg) will display a regular growl message and
CATMAID.info(msg) as well as CATMAID.warn(msg) have the title set
accordingly already.

fzadow/CATMAID,fzadow/CATMAID,fzadow/CATMAID,fzadow/CATMAID