Updated patch from #34 for goToPage issue with loop: false

[dokterbob]

This patch fixes several issues relating to goToPage() where loop: false.

If you disable looping and use a goToPage() the masterPage 0 will stay as invisible but potentially the next page will be visible (which shouldn't). Similarly, goToPage(2) would result in the destination page being hidden.

This pull request supersedes #34 and consists of the solution to provided by @linlex, which has been confirmed to work.