- Implemented but not tested yet
- All existing tests passing

* Not implemented yet. Currently always return false.
* Test exists and compiles, but is failing due to the missing implementation.

This is changed behaviour introduced with c9948142

Paths starting with "/" will be stripped of the leading slash now. Empty paths (or a single slash) will be interpreted to refer to the Module itself and hence return *this.

This logic is otherwise ofter required in code which uses submodule().

Before it had to be stripped for all use cases anyway, so it is better to leave it out from the beginning.

so dependencies can already ask for the new features

It was handing out only those control system accessors which do *not* belong to the particular ControlSystemModule, because the if condition was inverted.

Multiplier module: add modern constructor accepting qualified path names of input, factor and output

This function is indented for direct use when creating a HierarchyModifyingGroup, where this behaviour makes more sense. A "." as name of a HierarchyModifyingGroup will be the equivalent to HierarchyModifyer::hideThis.

For some reason this was disallowed and even tested to throw.

This actually makes the implementation also easier and more efficient.

* add HierarchyModifyingGroup

* VirtualModule: allow nested oneLevelUp etc.; simplify implementation

This is achieved by properly setting the _owner of each VirtualModule (unless highest level).

The simplification comes from then being able to use getOwner() instead of keeping track of "grandparents", and from using createAndGetSubmodule() instead of implementing something similar again in findTagAndAppendToModule().

* DataLossCounter constructor now takes qualified path to trigger variable