Have crossval tests use predict_partial_hazard
Have crossval tests use predict_partial_hazard

Since other predict methods are numerically unstable atm, use
predict_partial_hazard in k_fold_crossval tests. Since this method
works, I could remove the outer loop and increase expected result
because results are consistently good now (at .93 to 0.97).

Signed-off-by: Jonas Kalderstam <35a2c6fae61f8077aab61faa4019722abf05093c@kalderstam.se>

jstoxrocky/lifelines,CamDavidsonPilon/lifelines,wavelets/lifelines,nerdless/lifelines