Improve player movement

[Fueredoriku]

• There is now 0 drag on Y for players falling, giving no terminal velocity
• Remove quirk with floating point rounding by applying fixedUpdate too early
• Gave players more control when in air after jumping normally/falling
• Starting to hold crouch when you are in air until you land will now get players to crouch once they land
• Added dashing with much less air drag if you time leaps consecutively, see gif below
  • Dashes can be cancelled into a leap by letting go of crouch and holding crouch again while still in air
    

Future todo for other PRs:

• Dashing lines effect around screen of dashing player
• Dash jumping noice that goes up a pitch for each consecutive dash jump
• Leap noice
• Restructure some levels to accomodate for leap height (creating shortcuts to places of height and parkour opportunities)

[toberge]

Movement feels much better overall, especially now that you don't fall like in syrup, and the leapdash mechanic seems useful (though a little unfamiliar).

• I do wish we could differentiate this from an actual dash, and call it e.g. leapdashing.
• The jump curve still feels a little too rounded at the top, perhaps. It might be fine this way, I dunno.
• Leapdashing feels way harder on the ground in cratertown due to difficulty seeing when you are about to hit the ground. I think we should slap a texture on it again 😅