maximus: refactored some code, moving from main form to various classes

Moved some functionality from the main form unit, into the unitlist.pas
unit.
treeview: publish the OnKeyPress and OnKeyChar events
maximus: New method to remove an item from the UnitList
maximus: Adds the ability to remove a unit from the project tree

Simply select the node in the Project tree "Units" list, and press the
DEL key. If you don't save the project, the unit will still be part of
the project (easy undo feature). If you save the project the project
file will be updated - minus that unit.