Updated QML Oscilloscope documentation...
Updated QML Oscilloscope documentation
Removed note about using '-graphicssystem opengl' for better performance
as it only applies to Quick 1.
Change-Id: Ie4fb96afc1f8ae94c2d65d752fe7cfac281e750a
Task-number: QTRD-3509
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>