Support for other product types

[bartoszkubicki]

Hi, I see potential for huge ehancement which is adding support for other product type, especially composite ones. They require a lot of coding to fixture them. I am willing to contribute, but I decided to post this question first. Do you have any thoughts how it should look like? Every type has its internals, like methods gathered in type model. Not all of products follow interfaces and many times they lack some service contracts. I wonder if all fixtures should alter ProductFixture and ProductBuilder or should we separate that (virtual one, which is supported, is actually very simple variation of simple one). Looking forward to discussion.