Extend RichCompare function for arrays to handle string and unicode types
  using comparisons in C. 

Fix reduce, accumululate, and reduceat buffered method to be similar
  to the fix for the generic function (use a specialized inner loop, 
  but other than that it should be the same code as NOBUFFER...)

Add specialized scalar math functions so that scalars do not go through 
  the ufunc machinery but still use error-setting mode.
