Added `mode` to Multinomial to address #422. Passes all tests locally.
Removed redundant k parameter from Dirichlet
Fix to Dirichlet
Implemented categorical distribution
Finished implementing a draft of Categorical; no tests yet, and only works with non-HMC samplers
Implemented categorical distribution
Finished implementing a draft of Categorical; no tests yet, and only works with non-HMC samplers
Merge branch 'categorical' of github.com:pymc-devs/pymc into categorical

Conflicts:
	pymc/distributions/dist_math.py