latest release (v0.8.6) broke Blink master

[NHDaly]

The bug

It looks like the latest release of WebIO to v0.8.6 (JuliaRegistries/General#1473) broke Blink on master:
https://travis-ci.org/JunoLab/Blink.jl/builds/553312986

ERROR: LoadError: Javascript error	Error: Cannot find module 'debug'
Stacktrace:
 [1] #js#3(::Bool, ::Function, ::Page, ::WebIO.JSString) at /Users/travis/build/JunoLab/Blink.jl/src/rpc/rpc.jl:53
 [2] (::getfield(Blink, Symbol("#kw##js")))(::NamedTuple{(:callback,),Tuple{Bool}}, ::typeof(js), ::Page, ::WebIO.JSString) at ./none:0
 [3] #js#23(::Bool, ::Function, ::Window, ::WebIO.JSString) at /Users/travis/build/JunoLab/Blink.jl/src/AtomShell/window.jl:213
 [4] #js at ./none:0 [inlined]
 [5] #js#4(::Bool, ::Function, ::Window, ::Expr) at /Users/travis/build/JunoLab/Blink.jl/src/rpc/rpc.jl:61
 [6] js at /Users/travis/build/JunoLab/Blink.jl/src/rpc/rpc.jl:61 [inlined]
 [7] initwebio!(::Window) at /Users/travis/build/JunoLab/Blink.jl/src/AtomShell/webio.jl:16
 [8] #Window#17(::Bool, ::Type, ::Electron, ::Page, ::Dict{Any,Any}) at /Users/travis/build/JunoLab/Blink.jl/src/AtomShell/window.jl:70
 [9] Type at ./none:0 [inlined]
 [10] #Window#16(::Bool, ::Type, ::Electron, ::Dict{Any,Any}) at /Users/travis/build/JunoLab/Blink.jl/src/AtomShell/window.jl:44
 [11] (::getfield(Core, Symbol("#kw#Type")))(::NamedTuple{(:async,),Tuple{Bool}}, ::Type{Window}, ::Electron, ::Dict{Any,Any}) at ./none:0
 [12] #Window#20(::Base.Iterators.Pairs{Symbol,Bool,Tuple{Symbol},NamedTuple{(:async,),Tuple{Bool}}}, ::Type, ::Dict{Any,Any}) at /Users/travis/build/JunoLab/Blink.jl/src/AtomShell/window.jl:75
 [13] (::getfield(Core, Symbol("#kw#Type")))(::NamedTuple{(:async,),Tuple{Bool}}, ::Type{Window}, ::Dict{Any,Any}) at ./none:0
 [14] top-level scope at none:0
 [15] include at ./boot.jl:317 [inlined]
 [16] include_relative(::Module, ::String) at ./loading.jl:1044
 [17] include(::Module, ::String) at ./sysimg.jl:29
 [18] include(::String) at ./client.jl:392
 [19] top-level scope at none:0
in expression starting at /Users/travis/build/JunoLab/Blink.jl/test/runtests.jl:14

Context

As you can see in this comment, upgrading to the new version of WebIO caused the issue:
JuliaGizmos/Blink.jl#202 (comment)

And downgrading to a previous version fixes it:

(Blink) pkg> pin WebIO@v0.8.5
 Resolving package versions...
  Updating `~/.julia/dev/Blink/Project.toml`
  [0f1e0344] ↓ WebIO v0.8.6 ⇒ v0.8.5 ⚲
  Updating `~/.julia/dev/Blink/Manifest.toml`
  [0f1e0344] ↓ WebIO v0.8.6 ⇒ v0.8.5 ⚲

(Blink) pkg> test
   Testing Blink
...
   Testing Blink tests passed 

For completeness, here is the complete manifest info from the Travis output:

   Testing Blink
 Resolving package versions...
    Status `/var/folders/nz/vv4_9tw56nv9k3tkvyszvwg80000gn/T/tmpTWyZxL/Manifest.toml`
  [bf4720bc] AssetRegistry v0.1.0
  [9e28174c] BinDeps v0.8.10
  [b99e7846] BinaryProvider v0.5.4
  [ad839575] Blink v0.10.1+ [`~/build/JunoLab/Blink.jl`]
  [00ebfdb7] CSTParser v0.6.0
  [3da002f7] ColorTypes v0.8.0
  [5ae59095] Colors v0.9.5
  [34da2185] Compat v2.1.0
  [864edb3b] DataStructures v0.15.0
  [53c48c17] FixedPointNumbers v0.6.1
  [de31a74c] FunctionalCollections v0.5.0
  [cd3eb016] HTTP v0.8.3
  [9fb69e20] Hiccup v0.2.2
  [83e8ac13] IniFile v0.5.0
  [82899510] IteratorInterfaceExtensions v1.0.0
  [97c1335a] JSExpr v0.5.0
  [682c06a0] JSON v0.20.0
  [50d2b5c4] Lazy v0.13.2
  [1914dd2f] MacroTools v0.5.0
  [739be429] MbedTLS v0.6.8
  [ffc61752] Mustache v0.5.12
  [a975b10e] Mux v0.7.0
  [510215fc] Observables v0.2.3
  [bac558e1] OrderedCollections v1.1.0
  [fa939f87] Pidfile v1.1.0
  [189a3867] Reexport v0.2.0
  [ae029012] Requires v0.5.2
  [3783bdb8] TableTraits v1.0.0
  [bd369af6] Tables v0.2.6
  [0796e94c] Tokenize v0.5.4
  [30578b45] URIParser v0.4.0
  [0f1e0344] WebIO v0.8.6
  [104b5d7c] WebSockets v1.5.2
  [cc8bc4a8] Widgets v0.6.1
  [2a0f44e3] Base64  [`@stdlib/Base64`]
  [8bf52ea8] CRC32c  [`@stdlib/CRC32c`]
  [ade2ca70] Dates  [`@stdlib/Dates`]
  [8bb1440f] DelimitedFiles  [`@stdlib/DelimitedFiles`]
  [8ba89e20] Distributed  [`@stdlib/Distributed`]
  [7b1f6079] FileWatching  [`@stdlib/FileWatching`]
  [9fa8497b] Future  [`@stdlib/Future`]
  [b77e0a4c] InteractiveUtils  [`@stdlib/InteractiveUtils`]
  [76f85450] LibGit2  [`@stdlib/LibGit2`]
  [8f399da3] Libdl  [`@stdlib/Libdl`]
  [37e2e46d] LinearAlgebra  [`@stdlib/LinearAlgebra`]
  [56ddb016] Logging  [`@stdlib/Logging`]
  [d6f4376e] Markdown  [`@stdlib/Markdown`]
  [a63ad114] Mmap  [`@stdlib/Mmap`]
  [44cfe95a] Pkg  [`@stdlib/Pkg`]
  [de0858da] Printf  [`@stdlib/Printf`]
  [9abbd945] Profile  [`@stdlib/Profile`]
  [3fa0cd96] REPL  [`@stdlib/REPL`]
  [9a3f8284] Random  [`@stdlib/Random`]
  [ea8e919c] SHA  [`@stdlib/SHA`]
  [9e88b42a] Serialization  [`@stdlib/Serialization`]
  [1a1011a3] SharedArrays  [`@stdlib/SharedArrays`]
  [6462fe0b] Sockets  [`@stdlib/Sockets`]
  [2f01184e] SparseArrays  [`@stdlib/SparseArrays`]
  [10745b16] Statistics  [`@stdlib/Statistics`]
  [4607b0f0] SuiteSparse  [`@stdlib/SuiteSparse`]
  [8dfed614] Test  [`@stdlib/Test`]
  [cf7118a7] UUIDs  [`@stdlib/UUIDs`]
  [4ec0a83e] Unicode  [`@stdlib/Unicode`]

CC: @travigd

[NHDaly]

If it's easy to fix, that's great, and hopefully we can just re-release v0.8.6.

If it's not easy to fix, can we just revert the changes in v0.8.6 and instead release this change as v0.9.0 so that Blink can keep a compat boundary until we add compatibility with this new change?