don't include: Axis, RunSample, SpectraDetectorTypes, EmptyValues

When IPropertyManager::getValue fails to assign the property to the
specified type, a runtime_error is raised. Changed the error messages in
all (specific) cases to specify exactly what type it was expecting,
i.e. (const) shared_ptr<X> not just X or const X.

IPropertyManager::getValue has specialisations for shared_ptr<T>and
const shared_ptr<T> for most types. The only missing ones were
IFunction, TableWorkspace and WorkspaceSingleValue, and these have been
added.

Refs #9059

Refs #9078

Refs #9078

Refs #7819

in FunctionFactory and FitPropertyBrowser because it breaks existing code. Re #7623

Re #7623

Modified the GUI to handle the new type. Created BSpline fitting function which uses the new vector attribute to test it in the GUI.

The getParameter function returns by value but most places seem
to assign it to a reference. We get away with it as the parameter
is still in the same place in memory inside the vector but it's
misleading.

modified: DiffSphere.h
modified: DiffSphere.cpp
modified: DiffSphereTest.h

Added an attribute to CompositeFunction to enable/disable numeric differentiation.