FlxTouch / FlxSwipe / FlxMouseButton uses Float for ticks

[Gama11]

...even though ticks is an integer value. In theory, this could result in a loss of precision. In practice, ticks probably never gets big enough for that (not that I've done the math).

Looks like this is my fault - the original PR used Int for ticks: https://github.com/HaxeFlixel/flixel/pull/844/files#diff-ce309ba9294449fb970f15695e2127beR40

My PR, which was based on that one, used Float:
https://github.com/HaxeFlixel/flixel/pull/848/files#diff-68555b97d9c773e556d0e4a7c4cd960cR29

Cleaning this up shouldn't be a breaking change, since you can just assign an Int value to a Float (which is ironically probably also why this happened in the first place).