Sheldonys-zappa

* Packaging hotfix - thank Yunseop!

* Async responses (thanks Sean!)
* Remove setLevel call from common log
* Fix 1023
* Merge 1058, 1059, 1073
* Allow overriding of endpoint_url arg
* Add support for API Gateway stage variables
* Add AWS X-Ray support (thanks mathom!)
* Events take kwargs (Thanks mcrowson!)
* Detect P2/3 during `init`
* Include stage names in `slim_handler` zips
* Allow `-s` with `manage`
* Use same S3 bucket for global endpoints
* Fix bug with mixed-case packages
* Cache wheels, fix 0-byte wheels

* Add index prefix to each subsequent schedule expression for the same event (1051)
* fix/Only update CORS on resources which have an OPTIONS method (1036)
* Support for binary support and cors simultaneously (1011)
* Set Flask script name based on domain which the request was made to (1015)
* Fix SNS Async (1055)
* GZip for slim handler
* Force color option
* Various dep bumps

* Fixes 1001, don't override AWS env vars if k:v not set. Thanks Nik and Sean!

* Checks for the key 'Environment' when fetching remote lambda env vars (988)
* except BotoCoreError before general exception in zappa.cli.update
* make cookie hack case-insensitive
* Fix 998 - Make environment variable keys strings instead of byte arrays in python 3.6
* Add --disable_progress command line parameter
* 946 - Allow setting cors to false.
* 870 Lambda from outside
* Implement context header mappings - Feature Request Issue 939
* Separating out native AWS environment variables 962
* Rule name shortening
* Splintering aws_environment_variables from environment_variables (to avoid overwriting AWS native env vars).

* Add exclude for __pycache__ contents (943)
* Fix 937 - Use get_data
* Add support for configuring APIGW cache TTL and encryption 942
* Addressing 909: Don't load credentials for 'package' command