Jf zeromq display (#644)

* modified ZmqSocket to expose the SO_RCVBUF and SO_SENDBUF parameters. Modified DataStreamer.cpp to change the SENDBUF to 1MB when HWL is <10. Modified Datastreamer.cpp so that when HWL is changed, socket is unbind/rebind. Added rebind to ZmqSocket.cpp.
Changed slot UpdatePlot() in qdrawplot.h from privat tto public, added plot->UpdatePlot() after every axis range change, so the plots are updated immediatly and not at the next image.
Added onlinedisp_zmq program which connects to the receiver ZMQ port and show images and histos. Compiled against  ROOT 6.22/02. Added examples files.

* added setbuffer size also for gui, moved hardcoded values to a macro, removed unnecessary return of ok or success, added actual zmq exception message to could not create sockets error

* zmq: changing buffer size done within hwm

---------

Co-authored-by: mozzanica <l_mozzanica@mpc2012.psi.ch>
Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>

slsDetectorGui/src/qTabPlot.cpp

@@ -487,6 +487,7 @@ void qTabPlot::SetXYRange() {
     }
 
     plot->SetXYRangeChanged(disablezoom, xyRange, isRange);
+    plot->UpdatePlot();
     emit DisableZoomSignal(disablezoom);
 }
 
@@ -624,6 +625,7 @@ void qTabPlot::SetZRange() {
         zRange[1] = val;
     }
     plot->SetZRange(zRange, isZRange);
+    plot->UpdatePlot();
 }
 
 void qTabPlot::GetStreamingFrequency() {