Added:
- A scan axis validator method to SXRMB2DMapScanConfigurationView where
it changes the step spin box background colour to red if the start and
end points don't create a valid axis.  It also brings up a big red text
label to tell you what you did wrong.  Unfortunately, it does not stop
the program from crashing if users insist on trying to start a scan with
invalid axes.
- Changed the step spin box minimum values to be 0 to prevent the
possibility of setting negative step values.
- In SXRMB2DScanActionController, we added fabs to check scan axes are
valid.
Fixed merge conflicts.
Solve merge conflictions