Fix installation into an empty environment.

This is a quick fix for installing python-intercom in an empty virtualenv. Without this change, it would fail because it was trying to import the requests package inside intercom/intercom.py before the installation was actually done.

I know that this pull request negates 17ad38086ed90c7644994d131c025107e5c3599c, but i think that being able to install the package is more important.

To properly fix this, the intercom/__init__.py file should be reorganized to avoid importing extra modules.