Possible fix: Moment returns null when passing an empty string

https://github.com/moment/moment/issues/716

Corrected trim code

Modified create unit tests to reflect isValid

Added further create unit tests to check validation

Fixed parentheses on tests

Fixed further parentheses on a single test

If format with an invalid moment then expect !finite
Fix leftPadZero to only pad finite numbers

Corrected the number of expected assertions for the added tests

Corrected trim code

Modified create unit tests to reflect isValid

Fixed further parentheses on a single test

If format with an invalid moment then expect !finite
Fix leftPadZero to only pad finite numbers

Corrected the number of expected assertions for the added tests