Adding a poisson distribution factor and amending testDistributionFactorFunction.m to include a unit test for the factor.
Made the source a double rather than int
Merge branch 'PoissonBranch' of https://github.com/jneely1/dimple into Poisson
For Poisson built-in factor, added conjugate sampling of parameter, factor creation utility, additional tests, user documentation
Bug fix
Merge branch 'refs/heads/Poisson'

Conflicts:
	modelers/matlab/tests/algoGibbs/testFactorCreationUtilities.m