Fixing an issue where objects which were in a fatal collision state w…

…ith other objects were not throwing the FFL exception that they're supposed to throw to allow us to gracefully recover, and were instead just asserting the game. Notably, this was causing a frogatto issue when moth bombers would drop a bomb through other moth bombers, and assert if said bomb overlapped another one as it was spawned.

Added some new setter/getter functions for the camera position to fix…

… a regression where the camera was being positioned at the XY pos rather than the mid_XY.

Fixed FFL maps with the key "\" serializing literally, into invalid J…

…SON.

Fixes frogatto/frogatto#573.