Add matcher: Not()

[webmaster128]

A generic Not() matcher to get nice readable test code a la

CHECK_THAT(address1, Not(Equals(address2)));

Used and tested in Botan.

[philsquared]

Thanks. Been meaning to do that for a while!

[webmaster128]

Fine, thanks. I just rebased my other matcher onto current develop: #466 When this is in, I can follow-up with a bunch of matchers I have in the pipeline, like Integer and Boolean matching.