length_of_tag: new fun.
encode_tag: new fun.
_TLV1, _TLV: separate tag & flags args.
_OBJID: avoid cython warning.
APPLICATION: made more like CONTEXT.
check_pos, inc_pos, check_has: end-of-stream helpers.
_decode_tag: handle single & multi-byte tags, separate tag & flags.

TAGS_SEQUENCE, TAGS_SET: don't mix in FLAGS_STRUCTURED.
length_of_tag, encode_length, _TLV1, _TLV: API changes.

Issue #68.

start at particular point in time (relative to the end).

resync: limit option (0 for no limit).

'upgrade' in quotes because we ignore window updates.  seems to work anyway.
spdy_server_request:
  copy ':host' to 'host'.

connection: class variable to hold protocol name (for logging).

file_handler:
  Allow derived classes to add directory-listing behavior.
  unquote pathnames from the url.

FileLogger: new class.
StderrLogger: use FileLogger.
redirect_stderr: overwrite the copies in coro._coro as well.
  (otherwise a latency warning will cause the daemon to exit).

Removed non-existent dependency.

This way log processors don't have to duplicate it.

Adding E501 is working around a pep8 tool regression and should
be reverted when a fix is available.

Binary logging

Fix some readline issues with backdoor client

Facility: prepend each line with a facility id.
NoFacility: for one-module scripts.
StderrRedirector: capture stderr output to log as facility 'stderr'.
redirect_stderr: install it.
set_logger: new fun.
log: main interface.

- python prompt was confusing some readline commands
- save/restore readline history