1) Added the bayesian linear regression without given noisy variance.
2) Added the RealVector as the abstract class of SparseVector and CompoundSparseVector.
Merge branch 'origin/master'

Conflicts:
	workspace/ParallelMAB/src/edu/fiu/cs/kdrg/parallelmab/data/SparseMatrix.java
	workspace/ParallelMAB/src/edu/fiu/cs/kdrg/parallelmab/model/recommender/LinUCB.java