more logical rules handling

... mainly by distinguishing those that can be affected by the player
from those that can't
Merge pull request #126 from jvoigtlaender/idle-refactoring

more logical rules handling
fixing warnings (preventing compilation due to -Werror) in aibenchmark
Add warning for disabled JavaScript, refs [8948eda]
use the legend to indicate what transparency of pictures means (in movable mode), fixes #116
fixes mistakes in aibenchmark introduced with cd109e1
replay.julius is now using the js variable numSteps (closes #118)