Cherry-picking current changes on top of v0.1.0 release

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Fixing attribute indexing in NaiveBayes

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Renaming variables and methods to imply a clear sparse+position oriented naming schema

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Covering an additional case

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Removing unnecessary Map import

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Adding newline in LocalLearner and Indenting NB class

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Adding newline in NB class

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
Replacing DoubleVector by Map

Signed-off-by: Olivier Van Laere <vanlaere@yahoo-inc.com>
prepare for next development iteration