[Planner Dev] Planner modifications

[lbell <l bellonda virgilio it>]

Following my previous mail i made the following modifications to planner:

-configured the columns of the task tree
-added more columns
-put an item in the popup menu to edit them
-added a dialog to edit the column order (not fully working, but you can 
edit the label)

the saving/reloading of per user configuration is missing

what i want to hear from you is if the changes are in the right direction

The changes i have done are 'weird': the function names need some 
cleanup and so on; i want your approval before to continue.

I prefer to send to you my source tree (src and data/glade directory) if 
you want review the code or execute the program
To compile it, configure an official 0.12.1 src tree and copy my files in.

the size of the file is 80k. Can i send it to the list ?