Try to serialize requests to update the blog feed

Make a best effort to only allow one client/request to make the backend
HTTP request to the blog feed.

Addresses issue 928 (http://openhatch.org/bugs/issue928)
Remove deployment_settings.py from coverage checking

We do not really test the deployment_settings.py file, and that is OK.

No need for coveralls etc. to become unhappy that coverage decreases when
that file gets longer.
Remove a few more files from coverage
Use top-level manage.py as authoritative manage.py

This avoids a problem where we play path games and put
bytestrings on sys.path, resulting in pkg_resources.resource_stream
causing a crash in zipimport, which prevents pytz from being loaded.

Plus, it is just simpler.

Before and after this commit, the top-level directory (rather than
mysite/) was treated as the current working directory, so this should
not cause any breakage related to the current working directory.
Adjust Django debug toolbar to do non-ASCII-safe string operations

We should upstream this as soon as we can.
Import one module per line
Use tastypie serializer rather than raw yaml.load()

Thanks to @nedbat for rolling his eyes appropriately about using yaml.load().
Merge pull request #1417 from paulproteus/handle-unicode-paths

Handle unicode paths
Merge pull request #1418 from paulproteus/load-yaml-safely

Use tastypie serializer rather than raw yaml.load()
Merge pull request #1416 from ehashman/coverage-settings

Remove settings files, etc. from coverage checking
Merge branch 'master' of https://github.com/bobveznat/oh-mainline into bobveznat-master

Conflicts resolved:
	mysite/customs/tests.py