ENH: Medcouple for robust skewness estimation
ENH: Function allowing other functions to be applied using only 1d
    at a time
ENH: Robust Skewness from Kim and White
ENH: Robust Kurtosis from Kim and White
ENH: Helper functions for quantile.  Different from numpy.
ENH: Tests for medcouple
BUG: Made use of np.apply_along_axis and replaced custom version
General improvements to robust skewness and kurtosis
ENH: Generalized other texts to work along axis for standards
Simplified code to remove new weighted quantile function, instead
    use np.percentile
Removed incorrect test file in tools/tests/test_statstools.py
Added tests for multi-axis functions in stattools
Clean-up and documentation for robust skewness and kurtosis measures
Cleaned-up stattools
Added docstring for those missing
Added test for robust kurtosis
Fixed defect where ties were not handled correctly by medcouple
Reverted space additions around ** operator
Removed unnecessary float powers
Additional tests and fixes for 1-d inputs
Fixed issues using apply_along_axis with 1-d inputs
Added tests for axis=None
100% test coverage
Removed accidental CR in tools
Revert auto-spacing
TST: adjust test WLS llf, aic, bic because of different definition
ENH: Added flag to select excess or not
Allows raw values to be returned when excess=False
TST add test comparing WLS, GLS, rsquared differs see #1252
Added test for excess=False case
Merge branch 'WLS-llf-fix' of https://github.com/josef-pkt/statsmodels into WLS-llf-fix