fixing bugs on building trainstations and number of agents limited by the number of built train stations

minor bug fixes in node connecting algorithm

All starting positions are valid.
Check for feasibility of map is not yet done.

Now turns with the agent, encodes local information which can easily be enhanced by predictions, distance map and other things.

updated test to handle new predictor

Added potential conflict to tree observation as an 8th feature. ATTENTION this means that the observation space dimension has increased! will still check that this is handled correctly everywhere but looks good.