* Change the setting of the CSS transform properties on SVG nodes to set both the unprefixed version and the `-webkit-` prefixed version so that Blockly correctly renders in order browsers, such as Safari < 9 and iOS Safari < 9.2. For discussion of this issue, see https://groups.google.com/forum/#!topic/blockly/o3pERaRQhSg
* Correct the separation between the CSS transform property and the rest of the CSS that was in the variable misleadingly called "transform".
Improve performance of block dragging. This is a backport of the block drag surface from scratch-blocks. At the beginning of a block drag, blocks get moved to a drag surface which then translates using translate3d to avoid repainting the entire svg on every mouse move. At the end of the drag, the blocks are dropped back in the svg in their new position.
