Able to open files with ill-formed datetime, exported by SAS

[karakasa]

Fixed #846. Also added a basic test regarding SimpleDateFormat.Parse.

This fix is done by adding a compatibility stub into the aforementioned method allowing a leading space before one-digit hour instead of the regular zero.

Since the new approach utilizes DateTime.ParseExact, the change won't enable other ill-formed datetime strings.

[tonyqus]

It's nice to see a PR from a building architect.

一个被建筑设计耽误的程序员，哈哈