core::rt: Just a small fix to TcpStream
core::rt Wire up logging to newsched tasks
Tidy
Warnings
core::rt: Add a very simple ref counted pointer
core::rt: Add a simple channel type for passing buffered messages between Scheduler and Task

Called 'Tube' for lack of anything better.
core::rt: Make TCP servers work
core::rt: 0 is a valid TLS key
rtdebug off
core: Cleanup warnings
core: Move unstable::exchange_alloc to rt::global_heap
core::rt: Docs
core::rt: Register stacks with valgrind. #6428
core::rt: Wait for handles to close
Merge remote-tracking branch 'brson/io-upstream' into incoming

Conflicts:
	src/libcore/logging.rs
	src/libcore/rt/local_services.rs
	src/libcore/rt/uv/mod.rs
	src/libcore/rt/uv/net.rs
	src/libcore/rt/uv/uvio.rs
	src/libcore/unstable.rs
core::rt: Ignore tcp test multiple_connect_interleaved_lazy_schedule

Hangs on mac.
core:rt: A few micro-opts
core::rt: Add a test of standalone use of the runtime
core: Use a global lock instead of runtime lock for os::getenv, etc. #4726
core: Replace use of libc::getenv with os::getenv