Fix some typos

src/pipe.cpp

@@ -388,7 +388,7 @@ void zmq::pipe_t::terminate (bool delay_)
         state = term_ack_sent;
     }
 
-    //  If there are pending messages still availabe, do nothing.
+    //  If there are pending messages still available, do nothing.
     else
     if (state == waiting_for_delimiter) {
     }

src/pipe.hpp

@@ -98,10 +98,10 @@ namespace zmq
         //  Remove unfinished parts of the outbound message from the pipe.
         void rollback ();
 
-        //  Flush the messages downsteam.
+        //  Flush the messages downstream.
         void flush ();
 
-        //  Temporaraily disconnects the inbound message stream and drops
+        //  Temporarily disconnects the inbound message stream and drops
         //  all the messages on the fly. Causes 'hiccuped' event to be generated
         //  in the peer.
         void hiccup ();
@@ -181,7 +181,7 @@ namespace zmq
         //  active: common state before any termination begins,
         //  delimiter_received: delimiter was read from pipe before
         //      term command was received,
-        //  waiting_fo_delimiter: term command was already received
+        //  waiting_for_delimiter: term command was already received
         //      from the peer but there are still pending messages to read,
         //  term_ack_sent: all pending messages were already read and
         //      all we are waiting for is ack from the peer,