[#1106] Don't accept invalid URLs in resource proxy
[#1197] Add requirements file to fix the docs build on readthedocs
[#1197] Remove duplicate requirement which might prevent builds on rtd
Merge branch '1106-catch-invalid-urls'
Merge branch '1197-rtd-fix'
Merge branch 'master' of github.com:okfn/ckan
[#1197] Downgrade Sphinx to fix search on RTD

There is a bug on RTD that prevents the search when using Sphinx 1.2b1.

All details here:

https://github.com/rtfd/readthedocs.org/issues/443
Merge branch '1197-rtd-fix'