Support pagination for fetching users and rooms

[artfuldodger]

Enable pagination, without which it is impossible to get more than 100 rooms or users.

[coveralls]

Coverage remained the same at 100.0% when pulling e7eed9e on bonusly:support-pagination into 4a28188 on hipchat:master.

[rberrelleza]

Thanks! Could you add a unit test for the room pagination use case?

[artfuldodger]

@rbergman Sure thing! Added a new commit with some specs.

[coveralls]

Coverage remained the same at 100.0% when pulling 0053a11 on bonusly:support-pagination into 4a28188 on hipchat:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 73eeed4 on bonusly:support-pagination into aaa9350 on hipchat:master.

[artfuldodger]

@rbergman Need anything from me here to help get this merged?

[coveralls]

Coverage remained the same at 100.0% when pulling 3c6f725 on bonusly:support-pagination into 359bd59 on hipchat:master.

[rberrelleza]

Thanks for your contribution!