`find()`, `tapText()`

[rf]

find(): find titanium views matching string

• ios impl completed
• getCurrentViews() from Solo for Android impl

tapText(): tap a view displaying the given text (doesnt have to be a ti view)

• ios impl completed
• solo has a clickOnText method, so this is easy on android

[rf]

tapText() impl completed for android

[rf]

find() may be nontrivial on Android. We have getCurrentViews() from Solo, but there's no way to go from a native view back to the proxy as far as I can tell. So, we might need to somehow find the root TiUIView and then do a similar tree search as we did on iOS.