Made height/spinheight and height change values in replays more accurate

Another speedrunner Zippy Zero noticed how regularly the demo playbacks desynch when the player touches the ceiling in ball form. Turns out it was because of inaccurate height spinheight and height change values in replay files. This should fix it. This also fixes desynchs while jumping in reverse gravity,

Didn't change the demoversion since !1157 (merged), which does a change that hasn't been used in any release so far.

Edit: A little clarification to description.