Possibility to install without uvloop

[mojimi]

So, uvicorn automatically installs uvloop as a dep, but you can run without it.

Can we have a version/fork without uvloop? In Docker, Uvloop takes the majority of the build time, its really slow to build, so being able to skip it would really streamline it.

[erewok]

Most of the value of uvicorn in my own projects is that it is based on uvloop. If I didn't want something built on uvloop, I would probably opt for one of gunicorn's asyncio workers.

[euri10]

that's what #666 intends to do @mojimi so once a reviewer will have time I think you'll get what you want