[RFR] Introducing filter default value

[fzaninotto]

You can now use defaultValue() on filter fields, so as to filter the list as soon as the filter is added. Combined with an empty template, this allows to create "tagged" lists:

var user_id = 123; // currently logged user
var d = new Date()
var yesterday = d.setDate(d.getDate() - 1);
listView.filters([
    nga.field('flagged', 'template')
        .defaultValue('true'), // adds ?flagged=true to the REST query
    nga.field('author_id', 'template')
        .label('Mine')
        .defaultValue(user_id), // adds ?author_id=123 to the REST query
    nga.field('created_at', 'template')
        .label('Recent')
        .defaultValue({ gt: yesterday }), // adds ?created_at={gt:2015-08-31} to the REST query
]);

[fzaninotto]

There is a mystery that I can't explain: values uses one-way databinding in an isolated scope, yet the watcher on ListLayoutController gets notified when the values change. Weird, but works.