Bring Future support for IOStream read operations into IOStream itself.

This speeds things up in comparison to the _iostream_return_future
decorator by removing unnecessary abstraction and especially by allowing
Futures to bypass some of the hoops IOStream jumps through to ensure a
clean slate for its callbacks.
Remove _iostream_return_future from write and connect as well.
Add a fast path to stack_context when there are no active contexts.

This case is increasingly common now that coroutines are decoupled
from stack contexts.
Add a py26-trollius test case and fix a bug with timedelta on 2.6.
Compress all text/* content types, not just a whitelist.

Closes #982.
Add support for the websocket close status code and reason fields.

Closes #890.
Add python 3.4 tests to tox
Document the fact that tornado.options configures logging by default.

Add tests and comments for how to disable this configuration.
Make it slightly easier to disable by making the command line
flag case-insensitive and allowing `None` instead of the string "none"
when setting the flag in code.

Closes #952.
Catch up on next-release notes.