[WIP] make custom.js work with 3.0

Hi, 

These are the modification I had to do for custom.js to work on 3.0, 
need a little more work to have them also work on 2.3 without changes, 
but just in case you want to try. 

You should "just" need the following also: 
```
$ cat .ipython/kernels/haskell/kernel.json
{"display_name":"IHaskell","argv":["/Users/bussonniermatthias/.cabal/bin/IHaskell" ,"kernel", "{connection_file}"]}
```

And it should work with IPython 3.0.


Side note, conceal extension is quite cool.

got a kernel crash with `\.<tab>`
```
[I 14:55:55.516 NotebookApp] Saving file at /Untitled.ipynb
IHaskell: src/IHaskell/IPython/Message/Parser.hs:(125,3)-(129,59): Irrefutable pattern failed for pattern Data.Aeson.Types.Internal.Success parsed
```

You can easily reproduce programatically with `IPython.notebook.kernel.complete('\.',2, function(data){console.log(data)})`

Should I open a separate bug ?