A recent change had to alter how arguments were stored when calling a

spy, due to opcode changes in Python 3.6. Arguments in a call were

stored as positional or keyword arguments based on the function

signature and not on the call itself. That made some usage of kgb a bit

less than ideal, because instead of descriptive called_with() checks

using keyword arguments (matching descriptive calls), they'd have to

become less-descriptive calls specifying positional arguments.
This change enables passing keyword arguments to called_with() and

last_called_with() to check positional arguemnts. Instead of just

checking the list of keyword arguments in the signature, the entire list

of arguments are checked instead. This can help future-proof unit tests,

and just makes things more readable.

Unit tests pass on Python 2.7, 3.4, 3.5, and 3.6.
Tested with the other main codebases we use.