New managed thread API

Convert to new managed thread system for threads that cannot be reliably explicitly joined.

Nested tls support

• Adds support for nested tls (via proxy) by fixing tls channel handler attachment in the nested case

Host resolver creation update

• updates tests to use the new default host resolver creation function

Ref counting updates

• Test case updates for new ref-counting semantics on a number of types (aws_event_loop_group, aws_host_resolver primarily)

Websocket close time out task

Websocket close timeout (#283)

Cancel the CLOSE frame when it is blocked

New windowing implementation

• New windowing implementation that allows http streams on the same connection to have independent windows

HTTP/1 Chunk Encoder & Task Scheduling Revamp

HTTP/1 chunk encoder & task scheduling revamp (#272)

This fixes issue https://github.com/awslabs/aws-c-http/issues/270

Encoder changes:
- Combine the 2 state machines into 1.
- Encoder no longer deals with the lock when getting new chunks. The stream will be responsible for getting new chunks into the thread.

Task-Scheduling changes:
- HTTP/1 connection shares 1 lock with all its streams.
- connection has new `cross_thread_work_task` that moves work from `synced_data` to `thread_data`.
  - kicks off the `outgoing_stream_task` if necessary
- similarly, stream has a `cross_thread_work_task` for moving work from `synced_data` to `thread_data`.
  - it can also kick off the connection's `outgoing_stream_task` if necessary

Minor fixes

• Fix for uninitialized state of connection monitoring options

added another EOL to end of a test file, no logical changes.

v0.5.12

Added another stupid EOL to the end of a file. (#257)

Make sure connection manager tests are marked as net tests.

Plz net test ur net tests (#256)

Make these tests net tests.