This version removes python installation scripts, instead delegating Python installation to the user.

This release fixes:

1. Issue involving spaces within virtualenv DEST_DIR path ( Issue #20 )
2. Non-determinism involved in choosing Python executable to create virtualenv with when multiple Pythons are available on the computer.
3. zlib-related recommendation for OS X in the README ( Issues #22 / #23 )
4. the continuation of the ebcli_installer.py script beyond its failure to install the EB CLI.