Code review comment for lp://staging/~gary/juju-gui/env-help-text

Reviewers: mp+161418_code.launchpad.net,

Message:
Please take a look.

Description:
Help on empty canvas

The env view should show some help text when the canvas is empty.

Landing work from bcsaller that I modified.

https://code.launchpad.net/~gary/juju-gui/env-help-text/+merge/161418

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/8961049/

Affected files:
   A [revision details]
   A app/assets/images/empty_canvas.png
   M app/assets/javascripts/d3-components.js
   M app/store/endpoints.js
   M app/templates/overview.handlebars
   M app/views/environment.js
   M app/widgets/overlay-indicator.js
   M lib/views/stylesheet.less
   M test/test_environment_view.js
   M test/test_panzoom.js
   M test/test_service_module.js
   M test/utils.js