Fixed Regexp to not use ECMAScript 2018 features

[emoulson]

Previous version used regexp named capture groups, which is currently only supported in Chrome.
https://github.com/tc39/proposal-regexp-named-groups

Commented-out the named groups (I like the ability to name, so I want to reintroduce this if/when the proposal is better supported) and switched to using array references.

// hour: (typeof t.hour == 'undefined') ? 0 : t.hour,
        hour: (typeof t[2] == 'undefined') ? 0 : t[2],

Ideally, this can be fixed by making a better input parser instead of relying on a really long regex (#4).