Adds library and script files for make_bipartite_network

This functionality is being built to replace make_otu_network.py because that script has become nearly non-functional given changes to Cytoscape and Qiime including the biom format.
Updated script and added library rewrites as well as tests.
Added test data and outputs.

Verified that it works with %prog command in help documentation.
Addressed comments by @lkursell and @ElDeveloper
Addressed changes suggested by @ElDeveloper and @josenavas
Significant changes to script interface

Changes mades to the script interface so that the --md_fields option would be required. This, coupled with a change to the library, allows an individual to passbiom files which have jagged metadata (if metadata is list or string). Laura pointed out that this was likely the most common use case, and so it needed to be supported.
Added a space in doc string to resolve positional argument failure.
Modified so resolve jenkins failures

added script_usage_output_to_remove directories to the script.
updated to officially replace per_library_stats.py with print_biom_table_summary.py

fixes #592
removing script documentation
updated reference to per_library_stats.py in documentation
updated to use related function from biom-format
updated for backward compatibility
noted change
increased max acceptable p-value to reduce freq of stochastic test failures

also now provides more information error messages
Merge pull request #892 from gregcaporaso/issue-592

officially removed per_library_stats.py in favor of print_biom_table_summary.py
modified test to reduce freq of stochastic failures
Merge pull request #893 from gregcaporaso/issue-787

increased max acceptable p-value to reduce freq of stochastic test failures
Modifications to documentation to address comments.
Merge pull request #875 from wdwvt1/make_bipartite_network.py

new: make_bipartite_network.py