Fix custom resource path.

[Bekt]

Currently engineio.Server throws an error when the resource keyword argument is provided because it is not one of the options. These changes fix the issue.

On a side note:

I spent a few minutes trying to write a test case for this but the module seems very fragile. Some of the issues I've noticed:

• init_app() style does not work. SocketIO.on decorator uses uninitialized values
• The line if self.server is None: self.run(app) in SocketIO.test_client doesn't make sense because the run method never initializes self.server causing various NoneType attribute errors

[miguelgrinberg]

init_app() style does not work. SocketIO.on decorator uses uninitialized values

Can you give me more details about this please?

The line if self.server is None: self.run(app) in SocketIO.test_client doesn't make sense

Yes, this was required before to compensate for some initialization happening in the run() method, but I cleaned that up and isn't necessary anymore. I'm going to remove it.

[Bekt]

Thanks @miguelgrinberg. Looks like you fixed the first issue in the latest commit.