Export more functions

[jrnold]

It would be useful to export more functions since many of the unexported functions used internally are practically necessary to write custom linters.

[fangly]

I agree. See also #178

[jimhester]

Sure, send a PR with the additional functions you would like exported, be sure to document them appropriately as well.

[jrnold]

Okay, will do.

[wlandau]

@jrnold Do you have a tentative list? I would like to include ids_with_token().

[russHyde]

@jrnold could you confirm that the currently-exported functions are sufficient for you to write custom linters, please.

[jimhester]

I think all the necessary functions are now exported.