Use requests to fetch the repodata
Use requests to fetch the packages
Merge branch 'master' into requests
Correctly handle 304 when fetching repodata
Correctly stream the pkg url so that the progress bar works
Let requests handle the retries
Use requests in download(), and use that in fetch_pkg()
Make sure requests is installed in Travis
Remove unused import
Get rid of old urllib stuff
Enable proxy support in requests (from .condarc proxies)

I haven't tested it yet, but it should work.
Do the right thing when cannot connect to a channel
Give more information on an error
Correctly download to .part files
Merge branch 'master' into requests
Support file urls

This uses code taken from pip, mainly from
https://github.com/pypa/pip/blob/cdee19c77cf6514d42e2d1b7134f10b8ed36b63a/pip/download.py#L147-L217. Thanks
to @dstufft for pointing this out.
Fix potentially undefined variable
We apparently don't need this hack

See https://github.com/pypa/pip/pull/1792.
LocalFSResponse is no longer needed

See https://github.com/pypa/pip/pull/1794.
Revert "LocalFSResponse is no longer needed"

This reverts commit ee5bf7e8936c2d5e216347449ed0862de43f9675.