Use poll() on everything but windows machines so that large file
descriptors don't crash the interpreter, and will also work.

Issue #23
"Better" impl of poll in timeout functions.

Added return of error response in poll calls and safer type coercion
when converting from (double) seconds to (int) ms.
Modify setup.py so 'develop' command works.  This allows me to
pip install directly from my github repo.
Adds Justin Mayfield to AUTHORS