Fix Name Override With Inheritance

[plx]

This addresses current limitations mockolo from working as expected when mocking a protocol whose parent protocol that has a custom name override, e.g. this situation:

// In BaseProtocol.swift
/// @mockable(override: name = FakeBase)
protocol BaseProtocol {
    func register()
    var counter: Int { get }
}

// In DerivedProtocol.swift, will be a separate mock invocation
/// @mockable()
protocol DerivedProtocol: BaseProtocol {
    func like()
    func subscribe()
}

In such cases, mockolo currently fails to recognize FakeBase as the parent mock for DerivedProtocol, and thus fails to include the generated implementation from FakeBase in the body of DerivedProtocol.

The changes in this PR correct that.

All existing unit tests still pass, and I added new unit tests covering the behavior above.

The essential part of the change is explicitly maintaining a map from protocol names to the names of their mocks; it also addresses a few other places where the code implicitly only worked with the default naming pattern.

[CLAassistant]

All committers have signed the CLA.