Bug 24369: Add CORS support to output_with_http_headers()

Bug 24369: Add CORS support to output_with_http_headers()

This patch adds CORS support to output_with_headers(). It will use the
AccessControlAllowOrigin syspref to pick the value and set the Access-Control-Allow-Origin header.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/Output.t
SUCCESS: Tests pass!
3. Sign off :-D

Signed-off-by: Andrew Isherwood <andrew.isherwood@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>