ISSUE#113
Use tree to display existing file and data directory choices.
ISSUE#113
Add back in recognizing if the checkbox is clicked. This still doesn't
get communicated back to the user that an item has been chosen but it is
a start.
ISSUE#113
Build a tree of data directories for a project. This code is basically a cut
and paste of code from datadirs, except it works on a slightly different model.

Both sets of code could be combined. An issue will be opened up for this.