Rephrase name property on kwmock

Twice in the last few days I've hit the issue that you cannot mock or stub a property called "name" using Kiwi. I gather this is because KWMock has its own first class property called "name".

Since Kiwi is a generic library, and "name" is a common property to have on the objects being stubbed, I changed the underlying property on KWMock to mockName. This is following the convention of other properties on KWMock like mockedClass and mockedProtocol.

I added a unit test on KWMock exposing the inability to mock the "name" property (as it was returning the actual KWMock name property. Renaming "name" to "mockName" passes those tests.