Restore old Associative show method as print

[mbauman]

This should fix #7142 and JuliaIO/JSON.jl#72. The previous Associative show method is now the print method.

[JeffBezanson]

This should define show instead of print, since show is called by repr. It should work like arrays; see replutil.jl:26 (writemime).

[mbauman]

Updated. But I'm totally confused by the test failures. I don't understand how this would mess up the inference of expm. Here's the cause, cribbed from linalg3.jl:152:

julia> function foo()
           A5  = [ 0. 0. 0. 0. ; 0. 0. -im 0.; 0. im 0. 0.; 0. 0. 0. 0.]
           expm(A5)
       end
foo (generic function with 1 method)

julia> code_typed(foo,())
1-element Array{Any,1}:
 :($(Expr(:lambda, {}, {{:A5},{{:A5,Array{T,2},18}},{}}, :(begin  # none, line 2:
        A5 = hvcat(top(tuple)(4,4,4,4)::(Int64,Int64,Int64,Int64),0.0,0.0,0.0,0.0,0.0,0.0,$(Expr(:new, Complex{Int64}, :(top(box)(Int64,top(neg_int)(top(box)(Int64,top(zext_int)(Int64,top(getfield)(im::Complex{Bool},:re)::Bool))::Int64))::Int64), :(top(box)(Int64,top(neg_int)(top(box)(Int64,top(zext_int)(Int64,top(getfield)(im::Complex{Bool},:im)::Bool))::Int64))::Int64)))::Complex{Int64},0.0,0.0,im,0.0,0.0,0.0,0.0,0.0,0.0)::Array{T,2} # line 3:
        return expm(A5::Array{T,2})::Array{None,2}
    end::Array{None,2}))))

All tests pass if I comment out that one expm(A5) call.

[mbauman]

Even stranger: the test failure can be simply triggered simply by a print method for dict. See: https://github.com/mbauman/julia/compare/test-expm-failure

It may have something to do with the bootstrap procedure; defining Base.print interactively does not cause the same problem.