Button Description: Other Side Button

This moves a term to the other side of an equation.

For this to be possible there must be an equation (rather than an expression)
in the window and the term must be transferable to the other side in a single
operation.

For example 

		A+ B*C = D

The A can be moved to the other side (to give B*C=D-A), as can B*C, but not B
or C independantly.