Table demos with changes to scala.swing.Table.

TableDemo, TableSelectionDemo, TablePrintDemo, and TableFTFEditDemo.
SimpleTableDemo and SimpleTableSelectionDemo are withheld because the Integer
valued columns are not properly editable.

Changes to scala.swing.Table: columnCount, fillsViewportHeight, various print
functions, selectionModel, columnModel, defaultEditor.  The print functions,
especially, need review.

Why not:
```
case class Person( first:String, last:String, sport:String, years:Int, veg:Boolean)
val data = Array( Person("Kathy", "Smith", "Snowboarding", 5, false)...... )

def getValueAt(row: Int, col: Int): Object = col match {
case 0 => data(row).first
case 1 => data(row).last
....
}
```

Looks more like scala and avoids use of `asInstanceOf`