Added support for setting allowed origins
Switched to async allowRequest callback in engine.io for setting the allowed origins
Updated README to include origins
Moved the origins checking callback outside the origins getter/setter function.
Merge pull request #1485 from rase-/add/origins

Added support for setting allowed origins
Added a test to check access to client query params

It fails with the current upstream client! There is a pending PR to
make this test pass though.
Merge pull request #1492 from kevin-roark/add/query-test

Added a test to check access to client query params
Added backwards compatible and new style settability of engine.io maxHttpBufferSize