Add method: "is_element_clickable(selector)"

[mdmintz]

Add method: is_element_clickable(selector)

This should make use of:

from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
...
WebDriverWait(driver, 0).until(EC.element_to_be_clickable(element))

This method should return True if the element is clickable; False otherwise.

Note: An element could be visible without being clickable. Sometimes this distinction is important.

Note: SeleniumBase already has a wait_for_element_clickable(selector) method.