ZENGINE: Convert hardcoded constants to anonymous enum variables
ZENGINE: Throw a warning when a .scr file isn't opened
ZENGINE: Ignore .scr file lines that are empty
ZENGINE: Change the initializer list formatting to conform to how everything else is formatted
ZENGINE: Fix enum qualifiers
ZENGINE: Remove a verbose debug message
ZENGINE: Fix accidental redeclaration of the scale variable
ZENGINE: Move SearchMan directory registration outside ZEngine constructor

The launcher can do some extra changes within SearchMan after engine constructor.
This makes sure everything is set before registering more directories
ZENGINE: Create MousEvent class to handle mouse hovers/clicks
ZENGINE: Implement mouse event handling
ZENGINE: Implement push_toggle control handling