Introduce runUpdate and runQuery in Pure module.

Those functions would come very handy for testing state, which usually happens in pure environment. There was a problem though that the name `runUpdate` was occupied by a function to which it hardly suited. Since the new functions seemed to be more useful anyway, I simply dropped the old one. Since such a change broke backwards compatibility I increased the major version. 

@Lemmih, of course, changes like this require a confirmation from you, so let's discuss this.