Store and grant access to information on the assertion level

[mihammer97]

Currently, there are no deeper insights why a test failed (only which test.Test() failed).
E.g. when I have a Test like this and it fails:

test.Assert(All(), assertion.And(assertion.Contains(a), assertion.Contains(b), assertion.Contains(c)))

It would be nice to know which of the assertion.Contains caused the failure.
Currently, the assertions are evaluated, but the results are not stored.
Also, it would be nice if the information would be easily accessible.