New feature(s):
* Numbers: introduce IsPositiveOrZero() check.
--------------
Change(s):
* Numbers: introduce IsStrictlyPositive() as a substitute for IsPositive() which is now obsolete.
* Numbers: introduce IsStrictlyNegative() as a substitute for IsNegative() which is now obsolete.
* Improve error messages (consistency and relevance).
* Check.ThatCode(...).Throws&lt;T&gt;() now requires T to be an exception. This restriction ensures only Exceptions are proposed in autocompletion.
* Simplify the way you can extend NFluent by adding your own checks. Now, you can call: var checker = ExtensibilityHelper.ExtractChecker(check);  at the beginning of your check extension method, and then rely on its ExecuteCheck() or BuildMessage() helper methods to do the job. Note: the Checker is part of the NFluent.Extensibility namespace.

--------------
Bug Fixe(s):
* Fix the inversion between expected and actual error message for the .WithMessage checks on exception.
* Fix the issue with null value on Check.That(...).IsBefore(...).

New feature(s):
* Numbers: introduce IsPositiveOrZero() check.
* Numbers: introduce IsNegativeOrZero() check.
--------------
Change(s):
* Numbers: introduce IsStrictlyPositive() as a substitute for IsPositive() which is now obsolete.
* Numbers: introduce IsStrictlyNegative() as a substitute for IsNegative() which is now obsolete.
* Improve error messages (consistency and relevance).
* Check.ThatCode(...).Throws&lt;T&gt;() now requires T to be an exception. This restriction ensures only Exceptions are proposed in autocompletion.
* Simplify the way you can extend NFluent by adding your own checks. Now, you can call: var checker = ExtensibilityHelper.ExtractChecker(check);  at the beginning of your check extension method, and then rely on its ExecuteCheck() or BuildMessage() helper methods to do the job. Note: the Checker is part of the NFluent.Extensibility namespace.

--------------
Bug Fixe(s):
* Fix the inversion between expected and actual error message for the .WithMessage checks on exception.
* Fix the issue with null value on Check.That(...).IsBefore(...).

Update the release note to include the addition of the IsNegativeOrZero() check.
Update the release note to include the addition of the IsNegativeOrZero() check.
