[maven-release-plugin] prepare for next development iteration
change from https to git schema in scm
fix dependency issues when building against yarn
fix unit-tests that maybe fail sometimes; update .gitignore
remove duplicate data filer in Normalize.pig
remove duplicate sampling logic in normalization and rename DataFilter to DataSampler
Fix unittest
change default normalization samplerate as 1.0
filterExpressions doesn't work if the field is null
Merge branch 'master' into develop
add throwble check each place to make sure pig script running error can be invoked
Merge branch 'develop' of https://github.com/ShifuML/shifu into develop
Update .travis.yml
Merge branch 'develop' of github.com:ShifuML/shifu into develop
add exception catch in loading model file
move null check before flatten
[maven-release-plugin] prepare release shifu-0.2.3
Merge tag 'shifu-0.2.3' of github.com:ShifuML/shifu

[maven-release-plugin]  copy for tag shifu-0.2.3