fixed stochastic vol
First stab at revising Metropolis. Can now specify alternative proposals. Still need to add tuning.
Added tuning function for step functions
fixed up tutorials
Re-implemented tuning to keep logic in step function
Fixed proposal functions for Metropolis
Moved tests into pymc/ and made them easily runnable as a batch
Reverted matplotlib backend change in test_examples
Added clarifying comments to the tutorial.
Typo.
Minor edits to notebook.
Raise error for sparse matrix without scikits.sparse installed in hmc
More interpretable error for scikits.sparse missing.
Merge pull request #225 from johnmcdonnell/pymc3

More interpretable error when scikits.sparse is missing.
Reverted HMC
Merge pull request #214 from pymc-devs/metropolis

Add self-tuning to metropolis step method.
Fixed progressbar to show the proper number of iterations (n rather than n+1); silenced Matplotlib backend warnings on test_examples
Merge pull request #224 from johnmcdonnell/tutorial-fixup

Added clarifying comments to the tutorial.
updating python versions
Merge pull request #215 from pymc-devs/tutorial-fixup

Fixed up IPython Notebook tutorials to explain new syntax