Remove ETag from proxied responses, and add CORS header.
Really add Access-Control-Allow-Origin this time.
Merge pull request #387 from NICTA/noETag

Remove ETag from proxied responses, and add CORS header.
Merge branch 'master' of https://github.com/NICTA/nationalmap
Merge branch 'master' of https://github.com/NICTA/aremi-natmap into aremi-production