#54 project window navigation

[Oswald Buddenhagen]

the full-path view mode in the project window rocks, but
is still imperfect, as it simply does an alphabetic sort on
the flat list. i'd like to have a directory's files before (or
after) the subdirs.
another possible option: a true hierarchy, like in the file
selector. this should be helpful in large hierarchical
projects; i'm getting lost in the long list (even though the
full names are a big improvement already).
making the incremental search match on subcomponents
of the path would be cool, too. no, switching the view
mode all the time is no option.
and finally, the incremental search should be
case-insensitive.