isolate python-isms to better integrate with non-python kernels

[ivanov]

Right now, vim-ipython's :IPython command works if you just pass it the --profile haskell or the --profile julia flags. However, there is some left-over cruft that assumes we're running a python kernel: the Ctrl-C (KeyboardInterrupt) work-around, for example.

This issue is to keep track of the work in progress on this front.

• handle _pid shenanigans more gracefully
• set syntax highlighting based on source
• use profile to figure out kernel?