changes upload type checking to content-type header

also now sending proper content-type headers to s3 put cmd.
fixed prismic cors issue

see:
https://www.flowdock.com/app/projects/avalanche-canada/messages/431345
fixed auth0/prismic issue via http interceptor

if req.config.url starts with https://avalancheca.prismic.io/api then
set skipAuthorization to true on the http config object.
Revert "fixes prismic"

This reverts commit 47c86a764a303504d18a11eca3b2e25b75e91984.
Merge branch 'dev'