Ignore 0-length mousemove events, since Chrome seems to auto-fire these after mousedown/mouseup events in our case
Text updates relating to #203, including xml:space=preserve and inserting 0xA0 UTF-8 non-breaking spaces, and setText assert and cast
Adding assertion to warn about the situation in #196
Additional non-breaking space fix for the new DOM text rendering state
Adding corner/midpoint getters/setters to Node. see #201