Slow connections start player inside of blocks, too low

[satoshinm]

On the test server http://netcraft.herokuapp.com/, often the player starts beneath the top of the world, a couple blocks (4-5?), it seems to be related to having a slow connection (don't see this usually when testing locally) - maybe a race condition?

Thought I fixed this in #40 by ad983a5 but its cropping up again on the test server in production. Reported at https://forums.glowstone.net/topic/56/websandboxmc-web-based-client-providing-an-interactive-glimpse-of-a-part-of-your-server-using-webgl-html5/8

[satoshinm]

Maybe a symptom of satoshinm/NetCraft#107 WebGL warnings and errors in online mode only? The main loop was running too early. But the fix there only omitted rendering chunks too early, if !g->initialized.

Should handle_movement(dt) also not be called until initialized? Will this fix it, or is the problem deeper, a symptom of sending lots of block updates (B, commands) followed by a player position (P, command) right at the end, and the client takes a while to update all the blocks? Also consider satoshinm/NetCraft#136 Compact chunk updates.

Testing locally with NetCraft build 354 craft.html#netcraft.herokuapp.com%2080 I haven't seen this yet. I start above the top of the tree.