Fix signal handler for SIGINT

The loop now corretly exits when SIGINT is received.
Further reorganize code and create abstract classes
Clean up `trampoline`, `Listener`, `Hub.add` parameters
Move AbstractHub into abc, rename abc.Timer to abc.AbstractTimer
Fix import
Clean up imports
Check if timer is closed before closing

If we don't do this, it'll raise an Exception if the timer is already closed.
Various fixes
Create standard server implementation

These implementations are flexible and support several greenlet spawn
mechanisms. In addition, they create long-lived pyuv.Poll handles for the server
socket, rather than creating and removing the pyuv.Poll handle every time
GreenSocket.accept() is called. They are significantly faster than the default
server implementation from eventlet.
Clean up import/dependencies
Clean up a bit

There's still a lot to do, this module is a huge mess.
Bump version number
Clean up WSGI server

Further clean up this module. Still needs to be optimized.
Rewrite README, clean up project directory
Make gunicorn compatible
Remove docs and test

I will add these back in, module by module and rewrite anything that needs to be
rewritten.
Fix typo
Reimplement WSGI server (based on gevent)
Set up instance attributes

This is a cleaner way to set up a class. Now we know what the instance variables
are.
Remove/inline some attributes from `six`

We're not supporting Python 2, so no need for :mod:`six`. Might as well start
inlining those attributes now.