Installing pyqt only in Python 2.7
Installing pyqt only in Python 2.7

Since pyqt is not available on PyPI, we can't install
it using pip, relying only on apt-get to install it
if we are in python 2.7.

PySide is available, but in order to reduce build time
we also install it using apt-get when in Python 2.7.

The-Compiler/pytest-qt,pytest-dev/pytest-qt