Replace the wexpect.py with the latest release of Wexpect

[eoyilmaz]

Replace the wexpect.py with the latest release of Pexpect. I'm not very familiar with this module, and there is no comment in the code on why we have a wexpect.py instead of using the PyPI version of Pexpect. Reading the module documentation seems that this module is a modified version of a very old version of Pexpect. Using the modern version of Pexpect would benefit the code and possibly make the modifications obsolete.

[p5k369]

I think that's because of offering windows compatibility. https://pexpect.readthedocs.io/en/stable/overview.html#windows

[eoyilmaz]

Apparently there is a PyPI version of Wexpect and it is completely written from scratch, and it is a drop in replacement. I tried using it but until we fix #367 it is not going to run properly, but it is promissing.

[eoyilmaz]

Our wexpect is working properly right now, and I feel we don't need to replace it.