Avoid loading readline in the kernel
Avoid loading readline in the kernel

This bit of code was loading readline even when there was no need for
it. In a Qt console or notebook, try:

    'readline' in sys.modules
    'gnureadline' in sys.modules

I plan to rework this code more extensively once we've switched to
prompt_toolkit, but for now, this little fix should make the kernel
start slightly faster.

ipython/ipython,ipython/ipython