- Renamed security_context -> security_connector.
- Credentials are now responsible for creating their own connectors.

variables to set up the GRPC_LATENCY_PROFILER preprocessor macro so that timing
actually takes place.

statistics

This resolves a blocker stopping a clean linuxbrew install to work with one of
the wrapped libraries.

This allows us to get back to single binary tests where appropriate, which will help in-depth profiling efforts.
I've built this atop my smoke_test changes as they inspired me to get this done.

Enables the installation of dylibs to the MacOS prefix, and ensures that the
install name of the dylibs are just their file names rather than their relative
paths from project root when built.

This will allow us to re-use code generators in other kind of protoc plugins.

This is part of a change to ease internal usage of GRPC.

Adds a Makefile target called 'test_python' that first builds grpc, then call run_tests.py to run the python tests for the current configuration.

-) You can't assume bash is installed. Scripts needs to be cleaned out of bashisms.
-) You can't assume python is in /usr/bin. Use env instead.
-) AF_INET is in sys/socket.h
-) Added port_platform's basic structure for FreeBSD, based off Darwin.
-) FreeBSD doesn't have and doesn't need libdl for OpenSSL.