Speed ups and network bandwidth reduction
Another round of speed ups were achieved by using a combination of several techniques: use of compression and cache.
Loading the application takes now around 1.5MB of network, compared to about 5MB.
Loading layers was also reduced drastically. Typically, compression reduces the network traffic by 4 times. In other words, it's 4 times faster.
Even better, the browser's cache is used optimally: loading the same layer again is now almost instantaneous... unless it was updated in between.