New field type for page numbers

[dellsystem]

Used for sorting terms/notes. Integers need to be sorted correctly, and so do Roman numerals and any other page numbers that might be used.

Necessary if I want, say, the section page to contain notes and terms in order of appearance. Also for catching mistakes when entering page numbers (i.e., if the just-entered page number is less than the previously-entered page; not always an error, but often so).

Need to think about whether or not this is actually necessary or if timestamp is a sufficient proxy.

EDIT: Oh yeah. I needed this for determining the section from the page number. So it is necessary, if I ever want to be able to accomplish #13.