Added discrete variable support for Metropolis and a BinaryMetropolis step function
Fixed bugs in BinaryMetropolis
Cleaned up discrete type support
Added discrete variable support for Metropolis and a BinaryMetropolis step function
Fixed bugs in BinaryMetropolis
Cleaned up discrete type support
Merge branch 'metropolis' of github.com:pymc-devs/pymc into metropolis

Conflicts:
	pymc/step_methods/metropolis.py
Added modes to discrete distributions to address #244
Added call to numpy.random.seed to sample so that psample does not produce identical traces
Added stats and summary functions for trace
calc_interval now throws ValueError when there are insufficient elements.
Bugfixes to stats calculation
Created utilities.py to keep utility functions
Added autocorrelation and autocovariance functions to utilities.
Refactored summary to eliminate stats call
Generalizing stats functions; starting to add tests
Added tests for stats
Merge branch 'utils' of github.com:pymc-devs/pymc into utils

Conflicts:
	pymc/trace.py