PyQt5 and pandas
I just updated my conda installation to Pandas 0.20.1, and it does not load anymore since it depends on PyQt4 which was updated to PyQt5. 

To make Pandas 0.20.1 load with PyQt5,  I have to modify a function within the ``pandas.io.clipboard.clipboards`` module as follows:

#### Modified function within ``pandas.io.clipboard.clipboards``

```python

def init_qt_clipboard():
    # $DISPLAY should exist
    from PyQt5.QtWidgets import QApplication

    # use the global instance if it exists
    app = QApplication.instance() or QApplication([])

    def copy_qt(text):
        cb = app.clipboard()
        cb.setText(text)

    def paste_qt():
        cb = app.clipboard()
        return text_type(cb.text())

    return copy_qt, paste_qt
```
#### Problem description

The current behavior requires ``PyQt4`` by default, even if it is not needed to be used, which was giving me the error when import pandas:

``ImportError: No module named 'PyQt4.QtGui'``. 

Changing the module as described above solved the problem.

