Add automatic query continuations

[fhocutt]

It would be very useful if simplemediawiki handled query continuations (via continue or query-continue automatically.

[lahwaacz]

simplemediawiki will probably never be a full wrapper to the MediaWiki API (to keep its name) and as far as I understand it, it focuses on the low-level stuff.

This can be handled easily as described in [1], see my implementation.