MH Implementation

Hi Vijay,
please take a look to the implementation of what we discussed.
I have several exception when I run it, did you find the formatter statement?

Moreover, in the MHSampler class please check the run method: 
Can I use agent.renew() to get new samples (e.g. line 40 to get the initial state)?
After generating all the samples, I should count how many samples satisfy the evidence in the store, how can I do it?

Thanks,
Andrea