Jungling is rather than being in lane, killing the creeps that spawn in the Jungle parts of the map.
There is only one viable way to jungle with Tinker that won't make you underleveled or underfarmed but it is very difficult to master.
http-~~-//www.youtube.com/watch?v=vzlCAtZoE7g
Some screens from the Halloween Update inbound most likely next week courtesy of Cyborgmatt.
http://www.dotacinema.com/news/halloween-map-a-first-look