Deal with StaleElementException in wait_for_element_displayed (and _not_displayed)

This should address issues that we are having with StaleElementException

In this pull I have reverted contact_details.py back to what it was before the other StaleElementException fix was implemented to demonstrate that this change does in fact resolve that issue.

These changes are based on tests that I conducted today that suggest that the problem is that the element is becoming stale *between* the call to ```find_element``` and ```is_displayed```.