Checkpoint objects loading in

Checkpoint loaded in from editor and added to relevent data structure in
loadedLevel. The editor uses the first frame of the checkpoint activate
animation to represent them, so there should be no transform disconnect
between editor and level, even though the editor is displaying just one
frame while the game loads the whole sprite sheet (but still obviously
only displays one frame.)

When the player touches the checkpoint, all checkpoints are rest and the
one the player touches plays the animation and is set to be active
Death working, respawns at last checkpoint

The level class handles the death sequence, with the players Respawn
function actually moving the player. There is a slight delay and camera
pause on death, makes it look better.

Also fixed a bug I introduced when migrating animatedSprite away from
pointer animations to static memory animations.
Player spawns at base of checkpoint

Quick fix, the player was spawning at the origin of the checkpoint on
respawn, meaning there was a short fall to fix the ground. A little
maths fixes that.