updated readme

README.md

@@ -6,12 +6,14 @@ A basic QT interface:
 * plot each channel of a given data inlet in a separate plot
 * all Marker Inlets are plotted on one plot
 * a button to update the inlet list
+* a button to toggle selection of all inlets in the list
 
 This code has been edited from the ReceiveAndPlot example available at https://github.com/labstreaminglayer/liblsl-Python/tree/master/pylsl/examples 
 
 ## Requirements
 
 Python 3.x:
+* numpy
 * pylsl
 * pyqtgraph