#41 Batch Settings in VariableBox

[Reuben Grinberg]

Add Batch settings in VariableBox.

These should go probably underneath the Comment area (which will
now take up only 1/2 of the height of the box instead of all the
height).

The radio button options should be the following:
- Constant
- from _ to __
- Custom (write code in batchSetup())