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
add Python 2.5 to list of test targets
fix typo in mrjob.parse.urlparse() that was breaking Python 2.5
Merge branch 'master' of github.com:Yelp/mrjob into python25-tests
made tests/test_cmd.py work in Python 2.5 (with statement)
Merge pull request #781 from davidmarin/hadoop_jar_steps

Hadoop jar steps. Fixes #770, #772.
Allow partial AMI versions.

When matching EMR AMI versions, previously an exact match was
used. However, the API accepts partial versions, e.g. instead of
major.minor.patch, provide only major or major.minor. This works when
allocating a new job flow, but subsequent calls trying to reuse that
job flow would fail to find a match because the versions didn't match
exactly.

This just turns that test into a prefix test -- if the requested
version is a prefix of the job flow's version, the job flow is
considered a match.
Add test for partial AMI version matching.
Merge pull request #794 from ewencp/master

Allow partial AMI versions.