[ENH] Add colors

[ThibTrip]

Hello, first of all I am very impressed by this kernel! Would it be possible to get the correct colors for each kernel? Or at least have colors only for IPython? The code is completely black/grey when I work with it and do a HTML export.

Current

Expected

[ThibTrip]

I did a little bit of digging and was able to default the color to IPython (meaning the java syntax highlighting will be at least slightly false). So it seems the colors are done on the front end with CodeMirror.

Getting dynamical syntax highlighting will probably be tricky since we can only specify one language info. This is the change I made to default to Python:

class AllTheKernels(Kernel):
    """Kernel class for proxying ALL THE KERNELS YOU HAVE"""
    implementation = 'AllTheKernels'
    implementation_version = __version__
    language_info = {
        'name': 'all-of-them',
        'mimetype': 'text/python',
        'file_extension':'py'
    }

If you have an idea how this can be achieved I am willing to help :).

[minrk]

This is tricky, since Jupyter assumes only one language per kernel and highlighting is implemented in javascript, not the kernel. I think multi-language kernels need to define and provide their own codemirror mode for the switching somehow. I think calico may have found a way to do this?