Positive or 0 is NonNegative
Revert "Positive or 0 is NonNegative"

This reverts commit 0ac0f308d29e8800bc533948d85a806c8bd3e4f3.
"OutputArguments" cannot be 0, as this would lead to a MATLAB error
Fix for MFunction not checking its arguments: https://github.com/rsmenon/MATLink/issues/12
Assign $Failed to all output args
Disable automatic shortening of error messages to allow long error reports from MATLAB. Fixes #11
Since the ::errx message is thrown by multiple functions, attach it to MATLink to avoid confusion.