Add hide_ms option into msToTime and set consistent millisecond delimiter

[hongz1]

Currently "msToTime" output always include millisecond and need to be customized by end-user also. To achieve this, I added hide_ms option into msToTime function.

Also, all millisecond delimiter character format is not consistent. To follow ISO format of millisecond delimiter, I changed all millisecond delimiter character to dot (.) instead of colon (:)