Repeater combobox events

[interactivellama]

Fixes #1790 for @dkilgore

pageChanged.fu.repeater should now only fire once. Repeater's pageChanged event will now return an array with a [ [pageNumber], [dataObject] ] shape.

Additional help with paging and multiple combobox events
If repeater only has two pages of data, the combobox will be present. If a 3 is entered into the combobox the data key will return the data from the combobox's changed event

{ notFound: true, text: '3'}

The 3 is not present (since there are only two pages), therefore a notFound will be present in the data returned from the combobox. A 3 (or really a zero index 2, will still be passed into the repeater, but you can now check for the notFound key in order to revert to a valid page if you so choose.

Combobox was refactored, so that that changed.fu.combobox event did not fire twice when changed after typing and then using the enter key. Issues were also present that created multiple selected menu items due to previous item with .selected class were not being removed, but still determining what item selection by a query selector for .selected:first.

Individual tests
Individual tests for combobox were not being "taken down" and therefore tests were affecting each other and not isolated. It's a noop/return if you run .combobox() on a DOM element that has already been initialized.

Please note: There are combobox tests that test events fire once, but there are no tests to check that pagechanged.fu.repeater runs once or any tests related to that event at all.

[futuremint]

is there a reason you moved this above the early return?

[interactivellama]

It's so that val is defined.