1. added timerStt and timerStp around the sweeper for timing;
2. vectorize the loop for generating wtang - new weights;
1. vectorize the loop for generating wtang - new weights does not save observable time.
   in the case 3x3_asy_3x3_pin_7g, each sweep costs 0.08 second.
2. For current commit, after generating the new EXPT_vectoripol type bounds procedure, each sweep takes 1.1 second.
revert to use sweeper%expTableDat%EXPT since it's faster for now
vectorization of the ipol loop is done, but the RMS error is E-14 and MAX error is E-16 error.  In addition, one sweep takes more time.
commit before trying something that might messes things up
add a subroutine sweep2D_prodquad_P0_vectoripol2(sweeper,i) so that I could redo the vectorization and help see where the error comes from
tranposing exparg array does not introduce any error
all vectorized versions of sweeper coded