Removed a option alias "eta" for eta0
Added kld() UDF
[BUGFIX] Fixed to extend UDF
Add more checks in testPutAndGet()
Added a comment
Added open hash tables used in hivemall.mf
[BUGFIX] Fixed to shuffle in sweepAll() where buffer is not filled
[ENHANCEMENT] Added FixedEtaEstimator
Marked UDAFs as final class
Removed a line
[MODIFY] Moved deltaUpdates check statement
[MODIFY] Added constructors
[ADD] Added MutableFloat/INT
Added utility methods used in hivemall.mf
[CHANGE] Enabled CI in dev branch
[ADD] Supported a simple Matrix Factorization
Added a unit test for matrix factorization
[ADD] Added UDFs declaration for matrix factorization
[MODIFY] Updated to reflect recent changes
[MODIFY] Changed to build branches under dev/