Function Parse-Date-And-Time

Part of:

package metabang.utilities
( parse-date-and-time < spec > &optional < default-time > )
Converts `spec' to a universal time. Spec can either be a number, in which
case this is a no-op, a list of either 3 or 6 numbers, in which case it is
passed to `encode-universal-time,' or a string, in which case it is parsed.