norm(matrix) -> opnorm(matrix) in Julia 0.7

[stevengj]

It looks like may be using norm(matrix). In Julia 0.7, this will compute the Frobenius norm (vecnorm in Julia 0.6), due to JuliaLang/julia#27401. If you want the induced/operator norm as in Julia 0.6, use opnorm(matrix) instead, or Compat.opnorm(matrix) to work in 0.6 and 0.7 (JuliaLang/Compat.jl#577).

Note that, for testing purposes, rather than @test norm(A - B) ≤ tol, it is usually preferred to do @test A ≈ B or @test A ≈ B rtol=... (which uses isapprox).

[acroy]

Closed via #34.