Add some extra DBGMSG() calls to aid debugging
pubnub_http_timercb(): Fix potential removal of timeout after something resets the timeout
resubscribe_http_cb(): Call pubnub_subscribe_do() with wait==false

This fixes a bad race condition in case of the sync frontend - wait() is
called nested, which makes it eventually hang forever.
Merge remote-tracking branch 'origin/develop'