Added MLTask to run/schedule ML training and evaluation workflow
Merge branch 'develop' into ml-examples
Ignore exception if example table already created
Added verification for repeat runs of same task
1. Removed setter for session handle in LensConnection
2. Removed unnecessary config from lens-server's test site.xml
Merge pull request #165 from InMobi/ml-examples

MLTask workflow for combined training & evaluation
Initial draft for GRILL-618