Add symlinks for conda, activate, and deactivate into each environment
Make deactivate essentially the same as activate root

This, along with the symlinking of conda in each environment, makes it so that
you do not have to always have the root environment in your PATH, which allows
you to avoid "PATH leaking".
Start adding tests for activate
Install zsh in Travis
Add TemporaryDirectory to compatibility file
subprocess.Popen raises OSError when it fails
Fix activate to not add the root env to the PATH
Split up and add more activate tests
Don't add the root to the PATH if it is already there
Add some more activate tests
Add tests for the wrong number of arguments to activate
Add some TODOs for the activate tests
Work on getting activate to drop the root environment
Don't include python 3.3* in new specs in Python 3

This lets you create new environments in conda with packages that require
Python 2 without explicitly specifying Python 2. Python 3 is still added if it
is already installed into the environment (and the behavior for the Python 2
version of conda is the same as it has always been).
Fix some error message reporting
Use the root_dir in the activate tests for the syspath
add VersionSpec class, and tests
Fix the tests for what they should be for activate
use new class in MatchSpec
Set the PYTHONPATH in the script

Bash doesn't inherit environment variables, so setting it in Popen is
pointless.