Spin dryer requires bench enabled

[maurice stevens]

Now WBDiff must be enabled for the spin dryer to work.
This modification was made to cutback on our N2 usage.  The spin dryers 
require a high N2 purge.  Now it flows high N2 flow only when the bench 
is enabled.

-- 
maurice at stanford.edu

Maurice Stevens
Stanford Nanofabrication Facility
CIS Room 142, Mail Code 4070
Stanford, CA  94305
P. (650)725-3660
F. (650)725.6278