Misc fixes 05

a few fixes

closes #109  TestProbitCG failure on Ubuntu
closes #639  test folders not on python path        ( #639 not in commit message)
closes #565  omni_normtest doesn't propagate the axis argument
closes #563  error in doc generation for AR.fit 
closes #552  influence outliers breaks when regressing on constant

plus refactoring victims in ex_regression_plots