Add command line option to change jinja extension
"Merge pull request #65 from satiani/master\n\nAdd command line option to change jinja extension"
Port to new resolver API.
pip --use-mirrors is deprecated, remove.
Make pip use --allow-externals.

So it an find the webassets dev dependency.
Try to fix Travis tests.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Try to fix Travis tests.
  Make pip use --allow-externals.
  pip --use-mirrors is deprecated, remove.
  Port to new resolver API.
  Add command line option to change jinja extension