Make a number of Classes part of the psdata package

Moving CalcParser, StringDate, Author to psdata
Adding new Standard FIelds to Note

Adding Author and Date to the Note class.
Leveraging MetaMarkdown code for Notes

Copied and adapted some MetaMarkdown classes for use with notes.
Minor cleanup of comments
Added length to DataValueString

Added length method to DataValueString class
Minor enhancements

Minor enhancements to the DataValueStringBuilder class