Macros should enforce recording of only one mock invocation

[dmaclach]

Right now it is possible to write code like:

    id mock = OCMClassMock([NSUUID class]);
    OCMExpect([mock UUID]).andReturn(mock);
    OCMExpect([[mock UUID] UUIDString]).andReturn(@"Hello");
    [NSUUID UUID];
    [NSUUID UUID];
    OCMVerifyAll(mock);

That will pass even though it's obviously not what was intended. While this seems a little contrived, it's actually easier to fall into when using properties that themselves are being mocked so you have something like.

    OCMExpect([foo bar])
    OCMExpect([foo.bar bam])

We still do want to support the case however where foo.bar is not a stub.

I believe we should throw an assertion whenever the recorded stub is not the last invocation in the macro.

[dmaclach]

Note that I'm preparing a fix for this. Just wanted to record the issue.