Integrating gen_counts.R.

[andychu]

• Make it run as a script. Add a main(), which reads the params and true map, and writes out the counts file and the true histogram.
• Fix bug in analyze.R introduced in the last change. main() wasn't running because of sys.frames vs sys.frames()
• Get rid of unused HTML output in gen_sim_input.py and rappor_sim.py (replaced by regtest.html)
• gen_sim_input writes to stdout.
• rappor_sim.p uses --out-prefix, and other simplifications
• Separate the RandomPartition and GenerateCounts functions so we can print the true histogram as well as the counts
• regtest.sh has an alternate path for gen_counts.R

[ilyamironov]

Fixed the problem, and merged into master.