Hang when value-to-print is very large #703

bpython (or maybe curtsies, no idea) hangs when the result is very large.
Example:

>>> s = "hello" * 1000
>>> s
[hangs, never returns]

This happens on all of the following configurations:

• bpython version 0.17 on top of Python 2.7.13 /usr/bin/python on machine A
• bpython version 0.17 on top of Python 3.5.4rc1 /usr/bin/python3 on machine A
• bpython version 0.17 on top of Python 2.7.13 /usr/bin/python on machine B
• bpython version 0.17 on top of Python 3.5.4rc1 /usr/bin/python3 on machine B

Where:

• Machine A received the bugfix for Formatting fails when value-to-print is very large #607 back then. I'm not sure if OS updates have overridden that version.
• Machine B never received any manual updates, uses OS version.

It appears to be independent of #607, and I guess it's a regression.

Doing the same in plain python2 or python3 works flawlessly and quickly.