wrote methods to parse bootstrap options
attempted to rework bootstrapping, but haven't tested it
fixed bugs, updated tests that assumed a python bootstrap script.

tests now pass.
fix bug and use absolute paths in bootstrap script
added --setup command line option
Merge branch 'simplify_setup' of github.com:davidmarin/mrjob into simplify_bootstrap
added --bootstrap command-line option
added self._bootstrap to pool hash
Merge branch 'master' of github.com:Yelp/mrjob into simplify_bootstrap
Merge branch 'master' of github.com:Yelp/mrjob into simplify_bootstrap
Merge branch 'simplify_bootstrap' of github.com:davidmarin/mrjob into lyft-simplify_bootstrap

Conflicts:
	mrjob/emr.py
EMRJobRunner's default sh_bin is now /bin/sh
added test for creating new boostrap script, fixed bootstrap_python_packages option
started on setup.rst
whoops, need to export PYTHONPATH
documented --setup option
improved documentation of the setup option
added bootstrapping documentation (including cookbook)
added -y to apt-get command for bootstrap_python_packages
added docs for bootstrap options