V2 llmessage merge, incl. llcommon requisites.

Excluded llareslistener, as that appears to only be present for unit-testing
Excluded new SSL methods because, well, they don't work right reliably in v2 for me

indra/llmessage/llhttpclient.h

@@ -142,6 +142,14 @@ public:
 	 */
 	static LLSD blockingGet(const std::string& url);
 
+	/**
+	 * @brief Blocking HTTP POST that returns an LLSD map of status and body.
+	 *
+	 * @param url the complete serialized (and escaped) url to get
+	 * @param body the LLSD post body
+	 * @return An LLSD of { 'status':status (an int), 'body':payload (an LLSD) }
+	 */
+	static LLSD blockingPost(const std::string& url, const LLSD& body);
 
 	
 	static void setPump(LLPumpIO& pump);