Separate "Select All" button/checkbox support

[aleksmaksiuta]

Problem: User wants to use separate checkbox/button to select all items per click

Solution: Library provides an api to add a store/selection reference to be able to select programmatically all items via button, so I can:

1. Select all items using separate button.
2. Inside a callback function described in p.1 programmatically select all/partial set of items

[vdnhi]

Personally, I don't think this function is the goal of this library. It is very trivial to implement your own in your application to select all the items.

[aleksmaksiuta]

Personally, I don't think this function is the goal of this library. It is very trivial to implement your own in your application to select all the items.

Maybe I wasn't clear enough. After selecting all items via Select All button, my code adds class "selected" to selected items, but library doesn't update its internal state according the changes.