Cannot install python-stix without python-cybox being installed

[gtback]

This is minor, but should probably get fixed...

If you try to install python-stix into a clean virtualenv (or onto a clean system) using pip install stix, it fails because the cybox bindings are not already installed. Even though "cybox" is listed as a prerequisite in setup.py, due to the chain of imports shown below, setup.py cannot even be imported successfully.

  File "/home/gback/.environments/stix2/build/stix/setup.py", line 5, in <module>
    import stix
  File "stix/__init__.py", line 9, in <module>
    import stix.bindings.stix_core as core_binding
  File "stix/bindings/stix_core.py", line 15, in <module>
    import stix.bindings.stix_common as stix_common_binding
  File "stix/bindings/stix_common.py", line 15, in <module>
    import cybox.bindings.cybox_common as cybox_common_binding
ImportError: No module named cybox.bindings.cybox_common

Doing pip install cybox followed by pip install stix is successful, as a workaround until we fix this.

[ikiril01]

I've added a blurb about this to the README so that users are aware.

[bworrell]

I fixed this in my local copy last night but haven't pushed yet.

[gtback]

Awesome! Once we tag a new version and release on PyPI, we should be sure to take the note back out of the README.