Safeguard alpha property to a maximum value of 1.0
Safeguard alpha property to a maximum value of 1.0

If alpha is set to over 1.0, Displayobject would disappear.
Gama11/openfl,NenadBojkovski/openfl,openfl/openfl,NenadBojkovski/openfl,openfl/openfl,Gama11/openfl,Gama11/openfl,openfl/openfl,Gama11/openfl