openlayers/ol3 — pull request #1299 by tschaub (2013-11-21 00:44:24+00:00)
Title: Add transaction for tracking feature edits

As discussed in the weekly dev meetings and [mailing list](https://groups.google.com/d/msg/ol3-dev/rh6pe1-cJm0/NxOzjLWpeIQJ), this proposes an `ol.Transaction` to track newly created, modified, and deleted features.

Proposed `ol.Transaction` API:

* `setSource(source)` - start listening to add, change, and remove events on the vector source
* `getInserts()` - get a lookup of all added features
* `getUpdates()` - get a lookup of all changed features
* `getDeletes()` - get a lookup of all removed features
* `rollback()` - remove inserted, revert updated, and re-add deleted features

This is currently a work in progress and is based on the commits in #1282. Comments welcome.