Implement float(::Quaternion) since norm calls float on Julia 1.2.

Author: fredrikekre

src/Quaternion.jl

@@ -47,6 +47,7 @@ imag(q::Quaternion) = [q.v1, q.v2, q.v3]
 
 conj(q::Quaternion) = Quaternion(q.s, -q.v1, -q.v2, -q.v3, q.norm)
 abs(q::Quaternion) = sqrt(q.s * q.s + q.v1 * q.v1 + q.v2 * q.v2 + q.v3 * q.v3)
+float(q::Quaternion{T}) where T = convert(Quaternion{float(T)}, q)
 abs_imag(q::Quaternion) = sqrt(q.v1 * q.v1 + q.v2 * q.v2 + q.v3 * q.v3)
 abs2(q::Quaternion) = q.s * q.s + q.v1 * q.v1 + q.v2 * q.v2 + q.v3 * q.v3
 inv(q::Quaternion) = q.norm ? conj(q) : conj(q) / abs2(q)