Player can't jump over columns in higher FPS settings

[yak1r]

Hello,

This is a recurring issue, as already discussed within fifty-bird: games50/fifty-bird#2
As I explained there, the physics of the gravity calculation is wrong, and causes the gravity to be "too strong" for machines that run with FPS higher than 60

In this repo the mistake happens here

mario/mario/src/states/entity/PlayerFallingState.lua

Lines 25 to 26 in c1733f3

	self.player.dy = self.player.dy + self.gravity
	self.player.y = self.player.y + (self.player.dy * dt)

when adding the gravity to the player's dy it is not multiplied by dt, and the dy is decreased by gravity every frame, when the frame rate is higher, the gravity is stronger and at my machine (144 fps) the player simply can't jump over columns

as with fifty-bird, I prefer to suggest a solution and not just complain, see my Pull Request: #4