1.40	Wed Aug 06 2014 18:49:42 GMT+0400
	+ Add function get_period_key_by_timestamp and get_period_key_by_datetime

1.33	Wed Jul 30 2014 11:42:37 GMT+0400
	+ Fix pod SYNOPSIS :)

1.32	Wed Jul 30 2014 10:51:14 GMT+0400
	+ Add function timestamp_to_datetime
	+ Fix bugs

1.31	Tue Jul 29 2014 23:04:20 GMT+0400
	+ Release 1.31