Gantt/pert widgets commited

Hi,
I decided to commit the things I have been dabling with lately, as 
there seems to be somebody else that would like to contribute :)))
and I won't be able to do anything this weekend and not much next 
week.

The changes basicly adds Gantt and pert widgtes. 
It is now possible to:
Add projects/tasks/milestones, get it calculated and presented as 
gantt bars and pert diagrams.
In the pert diagram it is possible to link 2 tasks by single clicking 
on them (click parent then click child). Unfortunatly there is no 
feedback when you click the first node atm. If you click the same 
node twice the selection is cancelled.
Disclamer: The code is messy, tons of bugs, full of half started, half 
finished and missing things.
But, it compiles and runs, so...

Have fun.
-- 
Mvh,
Dag Andersen