Added replace parameter for setText

Requires https://github.com/admc/wd/pull/333 to be pulled first.

I also want to create a test for this in keyboard-specs.js but I can add that in another pull. 

Tested with the wd.js change and it works for me.
appium has a [style guide](https://github.com/appium/appium/blob/master/docs/en/contributing-to-appium/style-guide.md)