removed redundant functions
mouse controls are disabled when markers are on
markers are now draggable
added cursor lines to markers
added black background behind marker labels
removed keyPressEvent
markers now stay in same position even if RBW is changed
fixed marker behaviour while rbw is changed, re-enabled tunning via mouse while markers are on
cursor is now invisible
added custom infiniteLine widget
increased marker size, changed marker shape
marker colors are now white, removed radio button
added span/rbw labels
added span/rbw labels
markers now plot over trace
proper units used in RBW label while in HDR mode
rbw/span values display below respective labels
removed top/right axis of FFT plot
fix playback of old recordings
Merge pull request #73 from wardi/fix-old-recording-playback

fix playback of old recordings