openlayers/openlayers — pull request #297 by ahocevar (2012-03-06 22:32:48+00:00)
Title: tileloadstart event and fixed crossorigin handling

As a counterpart to the tileloaded event on the layer, this adds a tileloadstart event.

Only slightly related, but nonetheless important: this change includes a fix for a typo and improves handling of the crossorigin attribute for CORS image requests, which fixes a [Firefox issue](http://lists.osgeo.org/pipermail/openlayers-dev/2012-February/008392.html) that @fredj will like to get the canvas-to-greyscale example working in Firefox.