fix issues/39 and issues/40
allow the value of categorical column contain comma(,)
rewrite the stats step for shifu
fix the the stats pig and make it run successfully in horton
don't calculate median, since it take a long time to compute
fix the bug in binning
add Munro-Paterson algorithm for binning method
add pmml export
fix unittest after change test resource directory
fix bug
set speculative execution and make stats to run in more parallel
don't use those records whose tag is not in positive tag list and negative tag list to do data binning
fix the special characters in shifu stats
don't return those columns whose binning number are empty
PMML formet Model Spec

1. Added PMML validation Test Function
2. Correct the functionality of Category local transformation
3. Add Z-Scale Normarlized Cutoff handler
Merge branch 'hotfix-kevin-bugs' of https://github.com/ShifuML/shifu into hotfix-kevin-bugs
more comments and do merge also for AbstractBinning
Add labor-neg model spec
PMML Format File Test
refactor EqualPopulationBinning to make it run faster