[Halld-offline] nightly build and b1pi test on commissioning branch

[Mark Ito]

Folks,

To try to track down residual problems with the commissioning branches 
(hdds and sim-recon), the nightly build will be using those branches 
rather than the trunk as a temporary measure. The b1pi test will be 
using this form of the nightly build and will run daily rather than 
twice a week.

   -- Mark