Specification for stress test clients

Add HTTP request parsing

Fix timeout decoding logic for times that become infinite

python 2/3 compatible abstract servicers/stubs

Python: py3 compatibility for test runner & loader

Make a copy of ByteBuffer when writing

Reorder asserts to avoid TSAN failure

Make unix sockets optional

Make grpc-python ByteBuffer.bytes() linear

This extends the existing http parser to support requests as well as responses.

httpcli continues to exist and work as it has previously, though in the new
directory src/core/http (to reflect the fact the directory now contains code
relevant to parsing requests, which httpcli would not generally involve itself
in).

removed uchannels

Fix typo in GSoC ideas page

Exponential backoff for DNS retries

Lock the FD when initializing it out of the freelist

For GRPCOperation's, ensure finish _handler can only be called once

Mark mlog_test as flaky

Currently ByteBuffer.bytes() reads from the underlying grpc byte_buffer
a slice at a time, and appends each to a Python string (bytes). In
Python strings are immutable, so appending creates a new string by
copying the previous data.  This means the current implementation is
quadratic.

The effect is very noticeable when messages have repeated (or large)
string fields.  We traced execution between two services and observed
that when the payload size approached 600kb, the receiving service took
~10s at full CPU to read a response that had taken fractions of a second
the send over the network.

This commit changes ByteBuffer.bytes() to use an intermediate bytearray,
instead of strings, for the in-progress bytes.  Once all slices are
read, the buffer is converted to a string.

Letting the user override the code generation a bit.

Ensure that no #includes are inside of a namespace.

Support clang_complete based editor plugins

Add identity to static metadata accept-encodings bitmasks

Remove a spammy log

Properly mark proc used in call credentials for garbage collection

python3-compatible syntax for python examples

Add error output for failed ruby credentials plugin

Add extra error detail for pipe creation failure

Node: made call credentials properly use UV async events. Also deleted some log lines

Add needed include for udp_server_test

Make stack traces show up in run_tests.py logs

Add troubleshooting instructions