Remove one wrong import and added domino effects
make ground a LevelObject
use physical properties of the ground
debuging trajecotry agent

have to commit to get the stuff on my pc
use health instead of strength
no destruction of static blocks
add score for remaining birds
increased threshold for collision
Larger update introducing multi-shot framework

Added a framework to recursively search the space of sequential shots that might result into finishing a level. This should come in handy from level 4 onward, where usually more then 1 shot is required to clear a level. Framework is currently disabled, as cloning the level needs to be implemented. Secondly changed release point into ref point
make Level cloneable
removed slingshot from level (never used)
use CircleBird for Mighty Eagle
do not allow negative impulse
fixed cloning issue
enable multishot framework, not tested yet
removed unnecessary copying when cloning
fixed transformation of meters to pixel when updating the level
updated world scaling
fixed shooting angles
small change