Added crosshair example
Added crosshair example

pbmanis/acq4,meganbkratz/acq4,gvalentine/pyqtgraph,onlyjus/pyqtgraph,campagnola/acq4,welshjf/pyqtgraph,ericdill/pyqtgraph,duguxy/pyqtgraph,nmearl/pyqtgraph,mgraupe/acq4,ddamiani/pyqtgraph,meganbkratz/acq4,duguxy/pyqtgraph,tropp/acq4,carlomt/dicom_tools,campagnola/acq4,JenSte/pyqtgraph,ddamiani/pyqtgraph,acq4/acq4,wonkoderverstaendige/MausverPyler,meganbkratz/acq4,jlombacher/pyqtgraph,benvermaercke/pyqtgraph,mpvismer/pyqtgraph,mgraupe/acq4,wonkoderverstaendige/MausverPyler,pmaunz/pyqtgraph,pmaunz/pyqtgraph,acq4/acq4,hiuwo/acq4,acq4/acq4,hiuwo/acq4,hiuwo/acq4,Lx37/pyqtgraph,benvermaercke/pyqtgraph,meganbkratz/acq4,nmearl/pyqtgraph,campagnola/acq4,carlomt/dicom_tools,gvalentine/pyqtgraph,ddamiani/pyqtgraph,derricw/pyqtgraph,onlyjus/pyqtgraph,pbmanis/acq4,benvermaercke/pyqtgraph,ng110/pyqtgraph,ericdill/pyqtgraph,onlyjus/pyqtgraph,vallsv/pyqtgraph,gvalentine/pyqtgraph,tropp/acq4,mpvismer/pyqtgraph,JenSte/pyqtgraph,pbmanis/acq4,campagnola/acq4,derricw/pyqtgraph,tropp/acq4,petebachant/pyqtgraph,Lx37/pyqtgraph,tropp/acq4,stscieisenhamer/pyqtgraph,ng110/pyqtgraph,mgraupe/acq4,pbmanis/acq4,hiuwo/acq4,vallsv/pyqtgraph,mgraupe/acq4,welshjf/pyqtgraph,hiuwo/acq4,ericdill/pyqtgraph,petebachant/pyqtgraph,stscieisenhamer/pyqtgraph,acq4/acq4,welshjf/pyqtgraph,jlombacher/pyqtgraph,mgraupe/acq4