Added standard python installation capacity

The addition of a second module has motivated me to also add a
setup.py script, allowing installation into python. This will
also allow the hicluster modules to be more easily accessed by
other scripts now!
added set reporting and gene enrichment analysis

To improve usability of the venn diagrams, common_path now reports
those genes that are in the overlapping set. It also has more
intuitive coloration, and clearer labelling and figure legends.

The intersecting genes in a two-way venn are also subject to
enrichment analysis against GO and KEGG terms.
added ignore function to q value calculation

because the hypergeometric test for gene enrichment provides a
p-value distribution with an extreme skew of 1s, the estimation
of lambda is thrown off. Two workarounds have been added:

First, it is possible to analyse q values by ignoring the p-values
which have a value of 1. Typically this leads to very small
datasets! Second, it is now possible to override pi0_hat and give
it a value of 1, which is simply it's most conservative value for
estimation of q values (and is generally more appropriate than
simply ignoring all the p-values == 1).