- ALPN may not be available:
  - because OpenSSL does not support it.
  - because one of the peers does not support it.
- Tested manually end to end by forcing TSI_OPENSSL_ALPN_SUPPORT to 0.
  Also tested if only one of the peers supports ALPN.

Fix NPE for trying to add metadata to error when it was nil

Make run_jenkins.sh actually fail on failure.

Add PHP to jenkins

only build unbroken tests in Windows run_tests.py

Remove failing globs from examples and tests

Simplify metadata usage

Revised the state machine.

Fix docs on gpr_slice_unref.

Fix docs on grpc_op_type.

include string_util.h for the prototype of gpr_strdup and fix a typo.

Fixes two warnings in log_win32.c under msvc2015
log_win32.c(109): warning C4013: 'gpr_strdup' undefined; assuming extern returning int
log_win32.c(109): warning C4047: 'return': 'char *' differs in levels of indirection from 'int'

and corrects a typo in an error message

Only keep docker containers for tests that failed

Add Connectivity doc

fetch PR refspec for docker jenkins builds

Fix native callback signature to match with C#