Changes

Gunthers branch (#989)

* Refactoring to remove need for global stats scratch variables. larson-group/clubb#972

* Changing name of new stats_scratch variables to be more descriptive.

* Breaking up column loop in solve_xm_wpxp_with_single_lhs. larson-group/clubb#972

* Pushing loop into solve_xm_wpxp_with_multiple_lhs and breaking it up. larson-group/clubb#972

* Pusing loop into xm_wpxp_rhs and xm_wpxp_lhs. larson-group/clubb#972

* Pushing loop into xm_wpxp_solve and xm_wpxp_clipping_and_stats. larson-group/clubb#972