fix example bots responding to their own chats
updates to spawning

 * document "respawn" event
 * fix "respawn" event firing twice sometimes
 * remove `bot.spawn`
 * remove `autoSpawn` option. impossible to set to false now
 * fix sending spawn packet twice on init
 * update jumper example with more debug commands
 * refactor math and conversions into libs
 * `bot.dismount` with no vehicle emits error