[Patch] Add OnPaint and OnDrawItem for TToolBar

Original Reporter info from Mantis: 007

• Reporter name: lainz

Description:

It allow to customize the TToolBar with
- OnPaint event: change the background of the TToolBar
- OnDrawItem event: change the style of the TToolButton

Attached:
- Patch for lazarus trunk
- Screenshot
- Demo

Steps to reproduce:

Apply the patch.
Rebuild lazarus.
Run test.

Mantis conversion info:

• Mantis ID: 28029
• Build: 48926
• Version: 1.5 (SVN)
• Fixed in revision: r48938 (#f26e6ca2)
• Monitored by: » 007 (lainz)