[Glob2-ideas] improved pathfinding

[Leo Wandersleb]

hi guys

i just discussed an idea to improve pathfinding in jammed areas with my brother.

1. identify one-wide passages
(every square accessible from 2/8 directions is part of a one-wide passage)
2. trigger when a glob moves within a passage
3. make the passage propagate gradients in one way only so other globs will be 
forced into the same direction.
4. when the last glob leaves the passage open it again for both directions

although i guess the above would dramatically improve pathfinding without the 
need of human assigned one way areas as proposed earlier there remain special 
cases:
1. differently fast globs: faster globs will not be allowed to ignore the 
global gradient due to a collision. switch off local gradients while within a 
passage!
2. dead ends: if a glob realizes it can't reach its target without violating a 
passage-rule choose the best passage and make it switch direction

Greetings,

Leo Wandersleb

P.S.: The attached image shows an example of
blue=one-wide passages
each of those blue areas will have to be treated as one so direction switches 
on the whole length.