Mismatch description for AllOf changes to be consistent with other matchers.

    Example:
    is(2) against 3, would give a description of: was <3>
    allOf(is(greaterThan(2)), is(equalTo(4))) against 3, normally gives a
	mismatchDescription consisting of the description followed by the
	mismatched value, as in:
 	(is a value greater than <2> and is <4>) was <3>
    It now only resturns the actual mismatch as for most other matchers:
	was <3>