Merge pull request bitcoin#55 from rnicoll/bip0072-http

Add reference to RFC 2616 to BIP0072

bip-0072.mediawiki

@@ -38,12 +38,16 @@ described in BIP 70.
 
 Bitcoin wallets must support fetching PaymentRequests via http and
 https protocols; they may support other protocols. Wallets must
-include an Accept HTTP header in HTTP(s) requests:
+include an "Accept" HTTP header in HTTP(s) requests (as defined
+in RFC 2616):
+
 <pre>Accept: application/bitcoin-paymentrequest</pre>
 
 If a PaymentRequest cannot be obtained (perhaps the server is
 unavailable), then the customer should be informed that the merchant's
-payment processing system is unavailable.
+payment processing system is unavailable. In the case of an HTTP
+request, status codes which are neither success nor error (such as
+redirect) should be handled as outlined in RFC 2616.
 
 ==Compatibility==
 
@@ -59,3 +63,7 @@ Non-backwards-compatible equivalent:
 <pre>
 bitcoin:?r=https://merchant.com/pay.php?h%3D2a8628fc2fbe
 </pre>
+
+==References==
+
+[[http://www.w3.org/Protocols/rfc2616/rfc2616.html|RFC 2616]] : Hypertext Transfer Protocol -- HTTP/1.1