Allow disabling of manual column resize cursor in TableView

It would be useful for TableView to have a boolean property (e.g. resizableColumns) that would dictate whether the columns could be manually resized. The default would be true. If false, the mouse area between column headers would be disabled.

This would be useful in several situations:

• Columns have a fixed size.
• Columns are dynamically sized, and manual sizing is not permitted.