Replacing Numeric test to only validate against numeric (0-9) strings.

AlphaNumeric strings only contain characters a-z, A-Z and 0-9, and the AlNum test properly checks against that set.

The Alpha test properly only tests against a-z and A-Z.

The Numeric test, however, was using PHP's is_numeric(), which allows characters that are not strictly numeric:

- Plus (+)
- Minus (-)
- Exponent (e)
- Hexidecimal (x)
- Periods (.)

A new test named Number is added to perform the task previously filled by Numeric