Added new forced_root_block_attrs option that allows you to specify attributes for the root block.
Fixed bug where the custom resize handles didn't work properly on IE 11.
Fixed some issues with the resize.html manual test.
Fixed bug where selection bookmark elements would be visible in the elements path list.
Added forced_root_block_attrs to ForceBlocks.js and added unit tests for that feature.
Fixed old IE issue with ForceBlocks.html unit test.