[TIMOB-19064] Adding TableView to a default Alloy project results in invisible items

Reported via Q&A: https://community.appcelerator.com/topic/794/very-basic-start-with-tableview/12 The default Alloy app sets the backgroundColor of the Window to white. When you add a simple TableView and populate it with a data array instead of TableViewRows, the titles will by default be white as well on Android, which makes them invisible on the white background. We should either force the same default colours for Windows, Labels, TableViewRow etc for all platforms (probably in the SDK, not in Alloy TSS), or set none at all, which would in this case have resulted in a dark background and visible white titles on Android.