set action var to null by default;
reduced jobs at factory; added comments about node indices;
started writing a designdoc; removed some redundant TODO text;
added important TODO: describe the first minutes in game;
some first minute stuff; arrest attempts; skills and aircondition;
improved some enemy / mission handling stuff;
todo fix connection crossings;
moved pathfinding of actor into a new Path class and broke everything;
fixed most pathfinding at the start; there are still errors;
fixed all obvious pathfinding errors;
fixed: plotoverlay uses new pathfinding class now;
marked pathfinding module in TODO as fixed;
Merge branch 'master' into gh-pages