Assertions for >, <, /=, and within range (i.e. x < y < z)

I have now frequently enough needed to check that a value is within some expected range. We should have the following assertions for that.

• assert_less_than(expected_max, actual) (maybe also assert_less_than_or_equal_to(expected, actual))
• assert_greater_than(expected_max, actual) (maybe also assert_greater_than_or_equal_to(expected, actual))
• assert_within_exclusive(lower_bound, upper_bound, actual), assert_within_inclusive, assert_within_lower_inclusive, and assert_within_upper_inclusive
• and for good measure assert_not_equals(not_expected, actual)

While adding these, might as well add assert_equals for logicals