Const correctness for Workspaces

[Owen Arnold]

I cannot do this inside the execute method of my algorithm.

 boost::shared_ptr<const T> prop = this->getProperty("InputWorkspace");

I can only do this

 boost::shared_ptr<T> prop = this->getProperty("InputWorkspace");

This is bad because If I have an InputWorkspace as Kernel::Direction.In (not Direction.InOut) I do not, and should not be given the ability to modify that Workspace.

The problem is in IPropertyManager TypedValue.

It should just be a case of introducing this to get things working.

 /// explicit specialization for boost::shared_const_ptr
    template <typename T> operator boost::shared_ptr<const T>() {
      return pm.getValue<boost::shared_ptr<T>>(prop);
    }

[Stuart Campbell]

This ticket has been transferred to github issue ​12247