PEP8
Fixed custom Host

Closes #235
Mention "brew install httpie --HEAD".
Run tests against local httpbin instance via pytest-httpbin.
Fixed `python setup.py test`
Add the hawk plugin
Merge pull request #241 from ametaireau/patch-1

Add the hawk auth plugin
Cleanup
Handle empty passwords in URL credentials

Closes #242
Enable testing on PyPy 3
Added RequestItems named tuple for convenience.
'\' only escapes separator characters in req-items

It makes easier to work with Windows paths.

Closes #253, #254
Changelog typo.
Fixed --output=/dev/null on Linux

Closes #252
Merge pull request #249 from frewsxcv/patch-1

Enable testing on PyPy 3
Removed pytest-xdist

The test suite is much less IO-bound now with the local httpbin
instance (via pytest-httpbin). Therefore, paralelization is not
as helpful.
Improved terminal color depth detection via curses

Closes #244
Merge remote-tracking branch 'origin/master'
Changelog
Fallback to JSON highlighting if subtype contains json

Some JSON based formats like JSON Home Documents[1] don't
use a '+json' suffix, but simply contain json in their
MIME type. Also, some servers might use (outdated)
types like 'application/x-json'.

The JSON formatter can already handle those cases,
but the highlighter was ignoring them.

This commit will let the highlighter choose the JSON
lexer if no other lexer could be found and the MIME subtype
contains 'json'

[1] http://tools.ietf.org/html/draft-nottingham-json-home-03