wp_check_date_inputs: Helper function for wp_trend()
Description
Function that checks if the time span given by from and to (passed down from
wp_trend) are complying with logical constraints: from not prior to first
available data; to not past today; to not prior to from
Usage
wp_check_date_inputs(from, to)
Arguments
from
first date of timespan to check
to
second date of timespan to check