add xmpp_ctx_set_timeout()

strophe.h

@@ -117,6 +117,7 @@ typedef struct _xmpp_ctx_t xmpp_ctx_t;
 xmpp_ctx_t *xmpp_ctx_new(const xmpp_mem_t * const mem, 
 			 const xmpp_log_t * const log);
 void xmpp_ctx_free(xmpp_ctx_t * const ctx);
+void xmpp_ctx_set_timeout(xmpp_ctx_t * const ctx, const unsigned long timeout);
 
 /* free some blocks returned by other APIs, for example the
    buffer you get from xmpp_stanza_to_text */