* Plumb through the `--zip-safe`, `--always-write-cache`,
`--ignore-errors` and `--inherit-path` flags to the pex tool.
* Delete the unused `PythonDirWrapper` code.
* Split `PEXEnvironment` resolution into
`twitter.common.python.environment` and de-conflate
`WorkingSet`/`Environment` state.
* Removes the monkeypatched zipimporter in favor of keeping all eggs
unzipped within PEX files. Refactors the PEX dependency cache in
`util.py`
* Adds interpreter detection for Jython and PyPy.
* Dependency translation errors should be made uniform. (Patch
from johnsirois)
* Adds `PEX_PROFILE_ENTRIES` to limit the number of entries reported
when `PEX_PROFILE` is enabled. (Patch from rgs_)
* Bug fix: Several fixes to error handling in
`twitter.common.python.http` (From Marc Abramowitz)
* Bug fix: PEX should not always assume that `$PATH` was available.
(Patch from jamesbroadhead)
* Bug fix: Filename should be part of the .pex cache key or else
multiple identical versions will incorrectly resolve (Patch
from tc)
* Bug fix: Executed entry points shouldn't be forced to run in an
environment with `__future__` imports enabled. (Patch
from lawson_patrick)
* Bug fix: Detect versionless egg links and fail fast. (Patch from
johnsirois.)
* Bug fix: Handle setuptools>=2.1 correctly in the zipimport
monkeypatch (Patch from johnsirois.)