Add xpath suppot for FormRequest.from_response.
doc: removed broken proxyhub link from FAQ
correct docs for default storage backend
Merge pull request #196 from stav/master

The default storage backend is now DbmCacheStorage
doc: removed obsolete references to ClientForm
setup.py: use README.rst to populate long_description
improve mac os compatibility

Highlights:
* FifoDiskQueue: mixing buffered version of seek with unbuffered version
  of read causes problems
* BSD's find does not default to current directory
* gdbm needs to be closed before it can reopen the same file
* skip PIL tests if jpeg support is not available
Merge pull request #201 from alexcepoi/test-fixes-mac

improve mac os compatibility
add error details when image pipeline fails
Merge pull request #202 from saxicek/master

Image pipeline error improvement
QPS bench server and a useful spider spider to generate requests
Remove concurrency limitation when using download delays and still ensure inter-request delays are enforced
Support sending requests trough multiples slots in QPS exmaple spider
Add 0.16.3 release notes
Update docs/topics/commands.rst

A short change.
Merge pull request #204 from LuanP/patch-1

Update docs/topics/commands.rst
fix pylint and pep8 warnings
Altering delay is enough to auto throttle downloads
core: move download slot assignment post middleware evaluation
core: drop download inactive slots and get slot key from meta