convert objects to string

This little helper function allows to obtain a string representation for Matlab class instances.
Main feature is that properties which are also objects are converted recursively.
The recursion level is represented by tab intendation.
The maximum depth is definable, but infinite loops are taken care of automatically.

For more detailed object analysis checkout the UIInspect (#17935) program, and for Java class inspection see checkClass (#26947).
However, if you want a lightweight, recursive string representation this tool might just be a good choice.