Expose box splitting by making this algorithm a derived class of the BoxControllerSettingsAlgorithm. Also set sensible defaults for these splitting parameters. Fix the way that the workspace is created such that the box signal and error values are recalculated correctly.

...after a call to updateDataCurves().

When resizing a docked waterfall plot, the background was not being
refreshed properly. The issue was traced to this call, which is not
needed in this context.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

Conflicts:
	Code/Mantid/Framework/WorkflowAlgorithms/src/AlignAndFocusPowder.cpp
Re #7253

This fixes a bug if the sum of the bin boundaries is negative (in which
case the tests would always evaluate to false).

To help user and developer print a sensible message is valid-from date is too early

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>