Add svg icons from Django 1.9 and use static function

[claudep]

Fixes #172.

[coveralls]

Coverage increased (+0.03%) to 89.679% when pulling 93c0e57 on claudep:svg_icons into 323dc20 on dokterbob:master.

[dokterbob]

Thanks! If wait and submit aren't there yet, perhaps we should not close the SVG ticket altogether.

Any chance we could find equivalent SVG icons for these messages to fully finish this off?

[claudep]

It shouldn't too hard to convert waiting.gif to svg, but submitting.gif is animated, so it's trickier to convert (don't know the status of animated SVG in current browsers).

[dkdndes]

@DoctorBob if you are willing to add a non-standard lib, then check out https://loading.io/spinner/ - It would enable you to add a animated svg Icon.

[dokterbob]

@dkdndes Sounds like overkill to me.

Couldn't we just use one of their spinners and copy it as a direct replacement?

[dokterbob]

I guess the simplest option would be to add a static SVG spinner image and then use stepped CSS animation to animate it.