graphene:vec4-interpolate (v1 v2 factor result)

v1 -- a graphene:vec4-t instance
v2 -- a graphene:vec4-t instance
factor -- a number coerced to a double float with the interpolation factor
result -- a graphene:vec4-t instance for the result

The graphene:vec4-t instance with the interpolated vector.

Linearly interpolates v1 and v2 using the given factor.