Azure-functions-worker

In this release:

1. Support for raw binding data types
2. Handle empty ServiceBus messages
3. IOTHub metadata added to EventHub trigger metadata

In this release:

1. Fix binding for multiple out params
2. DateTime parsing fix
3. Add function app top-level directory as `__app__`
4. Use rawHttp body

Improvements
============

* Formalize worker logging (231)
(by elprans in ca32f025 for 231)

Fixes
=====

* Prevent user exception serialization from failing
(by elprans in 60680929 for 221)

* Unbreak test_cosmosdb_trigger
(by elprans in 273c3dca)

Improvements
============

* Add support for ServiceBus bindings
(in 09a3e3f9 for 133)

* Add support for Python 3.7
(in 44d32e5a for 166)

* Add HttpRequest.route_params property to access parsed route arguments
(in eb480487 for 198)

* Allow returning multiple messages in a queue binding
(in 5d62e629 for 192)