Added test for transfer() in LiquidProcessor

Tests whether liquid is transfered when there is no liquid yet at the
target.
Fixed return value of fillTile() when no transfer
Added test for transfer() in LiquidProcessor

Tests if transfer() works correctly with different types
of liquid at source and target.
Added test for fillTile() in LiquidProcessor

Tests whether no tiles are filled when an invalid
target position is supplied.
Changed EntityFactory to use getWorld() internally
Added test for LiquidProcessor for invalid target
Added test for fillTile() in LiquidProcessor

For liquid already at position.
Merge branch 'test-liquid-processor' of https://github.com/ZimonD/ContextCG7 into test-liquid-processor