Listview: New option to start with all items hidden when search input in blank

[toddparker]

There have been requests to use the listview filter as an autocomplete with local data by simply hiding all items if the search input value is blank. If we did this, it would allow a person to make what looks like an auto-complete by just adding a list and adding the filter option and this new option.

<ul data-role="listview" data-filter="true" data-filter-hidevalues="true">

The trickiest part is coming up with a clear name for this option. We should also divide if this should be a boolean or a value noting the minimum number of characters needed before showing the items so you coud require 2 or 3 characters before showing.

This feature would address issue #4539