Pitfalls in coupling extensions for Rabi-Dicke and JC

[cahitkargi]

1. if no qubit or cavity object is given, these extensions search the given composite object (self) and its subsystems for these types of objects and couple the first such instances. Such a default behavior/assumption might cause un-intended couplings if there are more than 1 instance of such systems. These extensions should raise error if there are more than 1 such instance for either of these systems/objects.
2. These extensions determine a qubit or spin object by looking at its .operator. This approach is very limited and does not work if their first term does not have an operator or have different operator than sigmaz/Jz (eg sigmax/Jx).