Python 3 Support

[fmagin]

When changing the Python Lib to /usr/lib/libpython3.so or /usr/lib/libpython3.7m.so instead of the python 2.7 lib on a current arch the kernel doesn't seem to start properly anymore. The plugin is loaded (and following plugins also load), the kernel json is placed in /run/user/1000/jupyter/ but the kernel never responds when connecting with jupyter console --existing

Not much of an idea what the reason could be. Maybe something changed with threads in python 3

[joshwatson]

I get this in stderr when I load this plugin with Binary Ninja using python3:

NOTE: When using the `ipython kernel` entry point, Ctrl-C will not work.

To exit, you will have to explicitly quit this process, by either sending
"quit" from a client, or using Ctrl-\ in UNIX-like environments.

To read more about this, see https://github.com/ipython/ipython/issues/2049


To connect another client to this kernel, use:
    --existing kernel-64418.json