Log Message:
py-pexpect: updated to 4.8.0

Version 4.8

Returned behavior of searchwindowsize to that in 4.3 and earlier (searches are \ 
only done within the search window).
Fixed a bug truncating before attribute after a timeout.
Fixed a bug where a search could be less than searchwindowsize if it was \ 
increased between calls.
Minor test cleanups to improve portability.
Disable chaining of timeout and EOF exceptions.
Allow traceback included snippet length to be configured via str_last_chars \ 
rather than always 100.
Python 3 warning added to interact.py.
Several doc updates.