refactor: Move parse_query_string to uri module
perf(Response): Eliminate extra list instantiation in _wsgi_headers
perf: Further optimizations for falcon.uri
feat(API): Default to using exception.handle in API.add_error_handler

This patch makes the "handler" param optional and defaults to using
a handler that is defined within the exception class itself. The
thinking is that this will encourage a good pattern in that the code
to handle a given error, and the error itself, are defined in the
same place (high cohesion).
chore(util.uri): Remove unused globals
chore: Bump version to RC3 and bring CHANGES up to date
chore: Bump version to 0.1.8
chore: Bump version to 0.1.9.dev1
perf: Use `callable` instead of testing for `__call__` attribute.

Should be faster, more elegant. See http://stackoverflow.com/questions/16388059/using-callablex-vs-hasattrx-call
Merge pull request #225 from JustinTArthur/callable_instead_of_hasattr

perf: Use `callable` instead of testing for `__call__` attribute.
chore: Update AUTHORS. Thanks Justin!
fix(falcon.testing): create_environ does not support None header values

This patch makes it so that you can pass in a headers dict with individual
headers that contain None, and those will translate to the empty string.
doc(README): Add request sink example
Fix inaccurate docstring for API._get_responder

The docstring for falcon.api.API._get_responder incorrectly stated
that the return from the function was a 3-tuple. This patch corrects
that to state that the return is a 2-tuple containing the responder
and the param dict, and adds some notes about the responder returned
for bad requests and no matching route.
Merge pull request #228 from jaypipes/doc-fixes

Fix inaccurate docstring for API._get_responder
doc(README): Say docs are a work in progress without actually sounding like an asshole
Merge pull request #230 from jordanrinke/master

doc(README): Say docs are a work in progress nicely
doc(README): Added new contributor. Thanks Jordan!
doc(README): Clarify that req.stream yields bytes from the request body
doc(README): Retitle second example