Set altered HTTPRequest attributes as parameters.
Un-force relative in format_date
test that invalid unicode doesn't raise 500
Prevent a deadlock if ThreadedResolver resolves a unicode hostname at module-import time.
Merge pull request #964 from ajdavis/resolver-deadlock

Prevent a deadlock if ThreadedResolver resolves a unicode hostname at module-import time.
Minor cleanups for import deadlock test:
* Avoid _test.py suffix for file that doesn't contain test cases.
* Resolve localhost instead of tornadoweb.org to avoid network dependency.
* Tighten timeout and add an alarm so failed tests don't leave orphaned
  child processes.
* Avoid busy loop while waiting for child to exit.
Merge pull request #945 from chrismcguire/request_body_property

Add properties corresponding to HTTPRequest constructor arguments
rase 400, not 500 on invalid unicode in decode_argument
Remove new HTTPRequest.if_modified_since property.

This property was unusual in that its getter returned a value its
setter would not accept, and was redundant with direct access to the
headers.

Use the property setters in the constructor instead of duplicating logic.
expect log message in test_decode_argument_invalid_unicode
Merge pull request #963 from minrk/invalid-unicode

bad unicode in URLs shouldn't cause 500
Improve log message for invalid unicode.

Truncate long values, and include the argument name if available.
Error handling in TwistedResolver
Add some markup to the old template intro docs.

Closes #967.
Merge pull request #965 from ajdavis/twisted-resolver-err

Error handling in TwistedResolver
Disable the "bad_host" tests on CaresResolver

This is an unfortunate hack, but c-ares doesn't handle fake NXDOMAIN
responses in the same way as other resolvers.
Mark another timing-sensitive test as skipOnTravis.
Fixes for soon-to-be-released py3-compatible version of pycurl.
Use a more reliable method to generate resolver errors.

On some platforms even getaddrinfo is fooled by the fake NXDOMAIN results.
Disallow ipv6 in curl-based tests.

The test servers only listen on ipv4, and it appears that libcurl 7.19.34
has regressed in its ability to handle the case when localhost resolves
to both v4 and v6 variants but only one works.

IPv6 was already disabled by default in simple_httpclient tests.