Make Cassette more eloquent

[maleadt]

I didn't like how it was always shouting at me.

The new Logging output also looks much better, because of indentation and proper stringification:

$ DEBUG=true julia -e 'using Cassette; Cassette.overdub(Cassette.@context(Ctx), println)("Hello, World!")'
┌ Debug: looking up method
│   signature = Tuple{typeof(println),String}
│   world = 0x0000000000006ba3
└ @ Cassette utilities.jl:94
┌ Debug: retrieved initial method
│   method = println(xs...) in Base at coreio.jl:4
│   code_info =
│    CodeInfo(:(begin
│          nothing
│          Core.SSAValue(0) = (Core.typeassert)(Base.stdout, Base.IO)
│          Core.SSAValue(1) = (Core.tuple)(Core.SSAValue(0))
│          Core.SSAValue(2) = (Core._apply)(Base.println, Core.SSAValue(1), xs)
│          return Core.SSAValue(2)
│      end))
└ @ Cassette utilities.jl:94
┌ Debug: returning overdubbed codeinfo
│   method_body =
│    CodeInfo(:(begin
│          nothing
│          Core.SSAValue(4) = (Cassette.func)(#self#)
│          Core.SSAValue(5) = (Cassette.context)(#self#)
│          Core.SSAValue(3) = (Core.getfield)(##cassette_overdub_arguments#1524, 1)
│          xs = (Core.tuple)(Core.SSAValue(3))
│          Core.SSAValue(6) = (Cassette.proceed)(#self#, Core.typeassert)
│          Core.SSAValue(0) = (Core.SSAValue(6))(Base.stdout, Base.IO)
│          Core.SSAValue(1) = (Core.tuple)(Core.SSAValue(0))
│          Core.SSAValue(7) = (Cassette.proceed)(#self#, Core._apply)
│          Core.SSAValue(2) = (Core.SSAValue(7))(Base.println, Core.SSAValue(1), xs)
│          return Core.SSAValue(2)
│      end))
└ @ Cassette utilities.jl:94
┌ Debug: looking up method
│   signature = Tuple{typeof(typeassert),Base.TTY,Type{IO}}
│   world = 0x0000000000006ba3
└ @ Cassette utilities.jl:94
┌ Debug: no codeinfo found; executing as primitive
└ @ Cassette utilities.jl:94
┌ Debug: looking up method
│   signature = Tuple{typeof(Core._apply),typeof(println),Tuple{Base.TTY},Tuple{String}}
│   world = 0x0000000000006ba3
└ @ Cassette utilities.jl:94
┌ Debug: no codeinfo found; executing as primitive
└ @ Cassette utilities.jl:94
Hello, World!

[maleadt]

we actually have this now, ref JuliaLang/julia#26265