Image source refactoring
Add a d3 example
Pass pixelRatio to canvasFunction
Pass state option to image source constructors
Add ol.source.ImageVector
Add image vector layer example
Merge pull request #1501 from oterral/vector-api

Add draw interaction tests
Merge pull request #1497 from elemoine/vector-api-d3

[vector-api] d3 integration and vector image
Merge remote-tracking branch 'openlayers/master' into vector-api
Update closure-util
Add error handler

If the server fails to start, display error message and exit.  Typically this is due to the address being in use.
Make olx types appear in API docs
Remove social links from d3 example
Example demonstrating a spyglass effect

Riffing off of the layer swipe example, this one demonstrates viewing one layer over another though a lens.
Handle case where resource has no imagery providers
Add example-behaviour.js to d3 example, thanks @tschaub
Add ol3 logo to d3 example
Merge pull request #1509 from tschaub/layer-spy

Example demonstrating a spyglass effect.
Merge pull request #1387 from ahocevar/olx-docs

Documentation error
Merge pull request #1508 from twpayne/vector-api-d3-no-social

[vector-api] Remove social links from d3 example