Commented Issue: Add BeNullOrWhiteSpace() & NotBeNullOrWhiteSpace() [11016]

Duplicate the current BeNullOrEmpty() & NotBeNullOrEmpty() but test for NullOrWhiteSpace.

Example.

string actual = "ABCDEFGHI";
actual.Should().NotBeNullOrWhiteSpace() // does not throw exception.

string actual = " ";
actual.Should().NotBeNullOrWhiteSpace() // does throw exception.
Comments: ** Comment from web user: TimMurphy **

Thanks, BeBlank is more than likely going to cover 99.9% of cases for me.

However. BeBlank uses IsBlank where I was requested the use of String.IsNullOrWhiteSpace. IsBlank tests the string does not include spaces where String.IsNullOrWhiteSpace tests for all white-space characters including tab, new line, etc. See http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx for more details.