TListBox cocoa widgetset implementation missing functionality

Original Reporter info from Mantis: djenkins @dfjenkins

• Reporter name: David Jenkins

Description:

1. Text entered in an editable ListBox field is not updated in widget
   
2. When listbox is in a scrollview the mouse and keyboard activity are not displayed in a Listbox edit field.
   
3. Now owner draw functionality.

Additional information:

1. Add textDidChange() function to TCocoaTextField that calls callback.SendOnTextChanged so that updated text can be caught
   
2. When TCocoaFieldEditor is used within a NSScrollView the needsDisplay path doesn't work out quite right. This shows up when mouse and keyboard action in the fields doesn't result in updates (but if you mouse to another app and then come back the updates are shown). Overriding setNeedsDisplayInRect_avoidAdditionalLayout that calls the setNeedsDisplay of the parent fixes this.
   
3. Allow for owner draw by overriding TCooaListBox.drawRow_clipRect() and setting up a call to LCLSendDrawListItemMsg().

Patch attached.

Mantis conversion info:

• Mantis ID: 32828