Changed int parameters to float

For wrapAngle and limit angle. Also removed local result variable.
Added documentation for bgColor
Specified bgColor format
Int to Float parameters, Parameter name changes

Int parameters changed to Float so Int casting is not necessary anymore.
Speed parameter renamed to Acceleration in accelerate functions for clarity.

None of these are breaking changes.
Int casts removed, typo fixed
Merge pull request #1050 from KeyMaster-/dev

FlxVelocity and FlxAngle type cleanup, bgColor documentation