Greengrass IPC client update

• New APIs added to the Greengrass IPC client (#199)

SNI, Pi fixes

• On Windows, always perform an SNI check even with an overridden root CA
• On Windows, properly honor the verify_peer = false option
• Fix instability with raspberry PI and input stream seeking by doing a better job of modeling file seek offset type and size.

Improved proxy support

• Http proxies can now be used with direct mqtt connections, not just websockets
• Samples updated with preferred proxy configuration parameters
• CRT version update
• • Fix bugs with the ECS credentials provider
• • Fix tls context initialization failures due to pem sanitization bug

Update awscrt and remove support for python3.5

• Python3.5 is EOL, remove support for it.
• Update awscrt to 0.11.19
• Add __version__ to the package

Fix Raspberry Pi wheels

• Use awscrt 0.11.17, which is working again on piwheels.org for python 3.7

Http bugfix

• More validation of HTTP/1.1 messages (#273); from aws-crt-python->aws-c-http (#190)

Fix memory leaks and MQTT race conditions

• BUGFIX: several memory leaks fixed
  • awsiot.eventstreamrpc (used by greengrasscoreipc) had circular references the gc could not clean up
  • awscrt.eventstream.rpc.ClientConnection was leaking its native part
  • awscrt.eventstream.rpc.ClientContinuation was leaking incoming headers
  • awscrt.http.HttpRequest was leaking its headers
  • awscrt.auth.AwsSigningConfig was leaking its native part
  • each call to awscrt.auth.aws_sign_request() was leaking native native data
• BUGFIX: several MQTT race conditions fixed
• BUGFIX: fixed errors when application is running on Windows for 21 days

Re-release: Fixes for Raspberry pi

This is a re-release of what should have been v1.5.11 which did not have the right tag name.

• Fix missing files in source distribution. This should fix the release on piwheels.org.
• Reduce amount of memory needed to compile. This should fix installs from source on older Raspberry Pis.

Updated Greengrass IPC client

• Updated Greengrass IPC client (#172)
• Updated MQTT to configure protocol operation timeout (#171)
• Update docs (#163)

EventStreamRPC connect ack bug fix

• New pypi wait strategy (#157)
• Updating dependency to pick up event stream RPC client fix. (#162)