Selenium

**Note** If you are updating to this version, please also update GeckoDriver to v0.15.0

* Fix python HTTPS encoding for python driver (3379)
* Allow Firefox preferences to be set directly in Options
* Fix shutdown and process termination (3263)
* Preventing exception if log_path is none or empty. Fixes 3128
* Add the W3C capability to Firefox for accepting insecure certificates
* Initial implementation of Pointer Actions
* Only skip tests if driver name matches a directory name.
* Update calls that return a pure object with keys to look for 'value' key
* Initial W3C Actions support
* fix docs output directory

* Add support for W3C Get Active Element
* Return when we use executeScript for faking WebElement.get_property
* Expand user paths and resolve absolute path for Chrome extensions
* Add support for verbose logging and custom path to EdgeDriver
* Update TakeElementScreenshot to match WebDriver specification
* Raise WebDriverException when FirefoxBinary fails to locate binary
* Fix getting IP for python 3
* Write Service log to DEVNULL by default
* Only attempt to remove the Firefox profile path if one was specified
* Added context manager for chrome/content in Firefox

* Fix regressions with python 3
* Add support for Safari Technology Preview

* new FirefoxDriver ctor precedence logic and moz:firefoxOptions support (2882)
* Add W3C Set Window Position and W3C Get Window Position
* enable log path setting from firefox webdriver (2700)
* Correct encoding of getAttribute.js and only load it once. Fixes 2785
* Encode the isDisplayed atom and only load it once

* Use atoms for get_attribute and is_displayed when communicating with
a w3c compliant remote end.
* Make it possible to specialise web element

* Updated Marionette port argument to match other drivers.