[Patch] TTreeView mouse selection

Original Reporter info from Mantis: biloky @biloky

• Reporter name: Joeny Ang

Description:

The following are addressed by this patch:

1. Multiselect with Shift, no msSiblingOnly; select a first child then select the parent (eg. on the attached example: select Item4, then Item0), this will select everything from Item4 to the last item
   
2. Setting MultiSelect to False does not clear selection
   
3. GetNodeAt(X,Y) should honor RowSelect state. When RowSelect=False, it will only return a node if X/Y falls inside the rect of the node and its icon.
   
4. Added tvoEmptySpaceUnselect option; clicking on white space will clear selection; when RowSelect=True, selection will only be cleared when the space after the last item is clicked.

Mantis conversion info:

• Mantis ID: 37145
• Build: trunc
• Version: 2.1 (SVN)
• Fixed in revision: r63232 (#257f842d), r63235 (#0d191847)