ENH: allow for custom patch artist and labels to the boxplots
TST: added tests for all of bxp and more boxplot tests
TST: fixed boxplot baseline image
TST: added baseline images for bxp
DOC/REF: added docstring for axes.bxp and refactored all references to outliers as fliers
REF/TST: update boxplot_stats test with outliers changed to fliers
ENH/TST: boxplots stats now takes a labels kwarg