Fix and test QR

Author: ChrisRackauckas

src/function_registration.jl

@@ -84,6 +84,7 @@ Base.:^(x::Expression,y::T) where T <: Rational = Operation(Base.:^, Expression[
 @register Base.conj(x)
 @register Base.getindex(x,i)
 @register Base.binomial(n,k)
+@register Base.copysign(x,y)
 
 Base.getindex(x::Operation,i::Int64) = Operation(getindex,[x,i])
 Base.one(::Operation) = 1

test/operation_overloads.jl

@@ -10,6 +10,7 @@ X = [a b;c d]
 det(X)
 lu(X)
 inv(X)
+qr(X)
 
 # test operations with sparse arrays and Operations
 # note `isequal` instead of `==` because `==` would give another Operation