pager: false bugfix

TL:DR - setting pager:false disables custom pager

When setting a custom pager, I want to be able to disabled all markup injected by the default pager, i.e. `<div class="bx-controls"></div>`.

If I pass `pager: false` then this stops the pager from working, even though `pagerCustom:` has a value.

This pull request repairs this bug.