Fixed: highlightOnPage() highlighting current page more than once

highlightOnPage() was highlighting the current page in addition to the page specified in the arguments instead of only that page specified.
Fixed: highlighting happening on current page even if called for another page

_highlight was being called for the current page to display highlights immediately upon calling highlightOnPage(). As such, if your current page was 2, and you called highlightOnPage(3), highlights displayed on both pages 2 and 3. Now, highlights only render immediately if the current page is equal to the one passed to highlightOnPage().

Fixes #128