Adds a Dev build target that includes the instrumentation (other features to follow) and a release build that excludes it.
Tidies up the instrumentation code itself ans moves to a separate location.
Chores:
Replaced literal screen dimension references with SCREEN_WIDTH and SCREEN_HEIGHT references, including obvious derivations.
Adds a Dev build target that includes the instrumentation (other features to follow) and a release build that excludes it. Tidies up the instrumentation code itself ans moves to a separate location.
Chores: