Add max_pages parameter to config file

[lucasmr]

This makes it easier to track smaller tokens, or reduce the amount of tokens being tracked. Somewhat fixes #276, until a more refined way of fetching the desired tokens is implemented.

[lyricnz]

Why change item from int to uint? With int we also have the possibility of using a magic-number like -1 which might mean (in future) "ulimited"

[lucasmr]

Zero could work like that as well. I just think uint is clearer and more readable, but I don't really mind.