ez.BoxFill one off on the x (maybe y too)

[JacobChrist]

Describe the bug
When using a ez.BoxFill the box (at least in the x-axis) doesn't go to the extents specified (maybe by design but if so its not clear in the manual.

The following image erases the trace with a box fill but the last pixel on the right is not erased.

A clear and concise description of what the bug is.

To Reproduce
Here is the code that generates the issue:

unction renderOscope(audio, gain)
	local result

	local x_min = 11
	local x_max = ez.Width-x_min
	local y_min = 10
	local y_max = 156
	local y_mid = (y_max - y_min) / 2 + y_min
	local y_max = 156
	local peak_to_peak = y_max - y_min
	local peak = peak_to_peak / 2
	
	-- erase previous scope
	ez.BoxFill(x_min, y_min, x_max, y_max, ez.RGB(0, 0, 40)) -- X1, Y1, X2, Y2, Color

	local index = 1
	for x = x_min, x_max, 1 do
		local left = ez.audio_getLeft(a, index) + .0
		index = index + 1
		left = left / gain * (peak)
		if(left > peak) then left = peak end
		if(left < -peak) then left = -peak end
		ez.Plot( x, math.floor(left + y_mid), ez.RGB(0, 0xff, 0) )
	end
end

Note: this bug was found in unreleased I2S firmware, so the ez.audio_getLeft() will need to be replaced with something equivalent if firmware is unavailable.