Change CAN to Can, to avoid confusion of thinking of acronym CAN.

re #7733

Conflicts:
	Code/Mantid/Vates/VatesAPI/src/vtkSplatterPlotFactory.cpp

Refs #7754.

and use it in CheckWorkspacesMatch. This avoids changes in ordering
within the map affecting whether the map is actually the same as another.
Refs #7743

Also, improved error message for LoadEmptyInstrument
when running child algorithm.
Refs #7743

The multimap was continuously growing as there was no way of checking
if a given parameter for a component was already loaded. The storage
is now a map with key <Component*,name> so that only unique
component/named pairs will be stored.
Refs #7743.

Refs #7708

The method that runs the algorithm in different ways has been moved to the top.

A comment breifly mentioning what the test does has been added.

Refs #2057

Refs #7708