Initial commit to branch const-timestep.
Reworking map editor from scratch.
Nothing really
Implementing basic map editor controls.
Basic working panel test.
Basic working cursor.
Many sheets converted to use alpha.
Sorta working modes.
Bg mouse cursor.
Button key bindings; scrolling made panel class methods.
Tile deletion added.
Some comments for modes.
Adding and deleting in background layer.
Some docs; organizing.
Layer visibility toggles with checkboxes.
Work on widget key bindings.
Loading and saving functional.
Trying to get wx dialogues to stay on top.
Enemy adding mode implemented (messily).
Float, not int.