Modify marginalizeTo to accept multiple targets
Add methods to remove duplicate variables
Modify marginalizeTo call to new signature
Alter marginalizeTo call to new signature
Add test for multiple marginalize targets
Add test for deDuplicating variables in Factor
Add no paramter deDuplicate
Merge pull request #122 from gtakata/DEV2.2

Dev2.2
Separate combineFactors into a separate function (no longer in
makeFactors(chain).

It needs to be invoked separately and can be applied to any list of
factors.
Revised tests to apply combineFactors as a separate function.
Reverted test due to removal of combineFactors.
Merge pull request #145 from gtakata/DEV2.2

Dev2.2
Merge pull request #144 from apfeffer/DEV2.2

Fixed BP underflow problem
Updates to SBT build file and .gitignore
Merge pull request #1 from p2t2/DEV2.2

Dev2.2