Don't set current working directory for external kernels

[fayeshine]

current working directory is binded with both ipython console directory and the editor file directory, which is not suitable for remote kernel.
I use a remote kernel (by redirect the port to a external server), and the file directory is totally different for ipython console and my local file directory.
Can we separate these two directory as before or at least add an option to separate them?

[ccordoba12]

We totally missed this use case. We'll fix it in 3.2.5.

[ccordoba12]

@rlaverde, please work on this one.