Fix jupyter notebook usage: Replace stty with shutil.get_terminal_size

[jdanbrown]

In an ipykernel (e.g. when in a jupyter notebook), install_extras emits a spurious error to stderr:

$ jupyter console
>>> import prettyprinter; prettyprinter.install_extras(warn_on_error=False)
stty: 'standard input': Inappropriate ioctl for device

The problem appears to be the usage of the stty shell command:

>>> import os; os.popen('stty size', 'r').read()
stty: 'standard input': Inappropriate ioctl for device
''

Replacing uses of stty with the builtin shutil.get_terminal_size() appears to avoid this:

>>> import shutil; shutil.get_terminal_size()
os.terminal_size(columns=133, lines=75)

[jdanbrown]

Sorry for the multiple commits, this is ready for review.

[tommikaikkonen]

Thanks! LGTM. Sorry for the delay in merging this.

[tommikaikkonen]

Released to PyPi in https://github.com/tommikaikkonen/prettyprinter/releases/tag/v0.14.0!