New functions and updatates

New:
countdays() - number of day amoung 2 timestamps
datetimeboundary() - from given timestamp(s) and level of data
(hour/day/month/year) return start and end timestamp
getweekdays() - count number of each weekday in given period
strrpos() - replacement of older version of PHP where re not functions
stripos() and strripos()

Update:
parsedate() - chnager regular to preg_match