Converter: correct logic for byte monitor orientation
Converter: preserve transparency of EDM Text Controls
Converter: Added a font scaler instead of look up table.
Converter: improve XY graph conversion

 - Add log scales if chosen
 - Set empty strings for axis labels if none present
 - Remove legend by default
 - All fonts in EDM graphs are the same
 - All EDM graph borders are one pixel, black
Converter: no legend on EDM 2DProfileMonitor
Converter: correct labels for related display

If there's no text on the original, put "" instead of the default
label.
Check if file exists before opening OPI

This prevent an issue where an OPIView opens
even when the OPI file doesn't exist. It also
prevents mutiple exceptions occuring in this
case.
Merge remote branch 'cssgh/master' into converter
Merge pull request #645 from dls-controls/converter

EDM converter improvements
Merge pull request #647 from ControlSystemStudio/bug646

o.c.archive.engine: For -skip_last, assume current time as last stamp
Merge pull request #649 from dls-controls/bug648

Check if file exists before opening OPI in View
Merge remote-tracking branch 'origin/master' into sns4