Fix referer check

Dependencies

• [2] 2P35LNRY Add XSRF protection for POST requests
• [3] LZVO64YG Merge in the first bits of the API work
• [*] J5UVLXOK * Start of a basic Catalyst web interface.

Change contents

• replacement in src/lib/Hydra/Controller/Root.pm at line 69
  [2.303]→[2.303:361](∅→∅)
  − unless defined $referer && $referer eq $base;
  [2.303]

  [2.361]
  + unless defined $referer && substr($referer, 0, length $base) eq $base;