(bug 40658) Support query continue in CheckUserLog API

Adds support for query continue to CheckUserLog API, and as a result,
also fixes the incorrect limit issue.

Adds support for a direction option and corrects limit parameter in
the example URL as well.

Change-Id: I2fa2cae10831c2da21002232a812e9c7721a4c0f
Merge "(bug 40658) Support query continue in CheckUserLog API"