[TIMOB-10395] iOS: Support for native UITableViewCell native Cell Styles on Ti.UI.TableViewRow

The performance of native UITableViewCellStyles is far superior of the custom rows/cells and the best choice for larger table views. As of now, this is still not implemented. I think this is due to the way Titanium deals with Rows, as it doesn't exposes the UITableViewCell to Ti high level API's thus not allowing the definition of a property mapped to UITableViewCell::initWithStyle. So, as we can actually use the default cell style by using the title property on Ti.UI.TableViewRow, I think we could have something like:

row = Ti.UI.createTableViewRow({
    style: Ti.UI.iOS.ROW_STYLE_SUBTITLE,
    title: "This is the main title",
    subtitle: "This is the native subtitle"
});

Where the *style* property could have values like: ROW_STYLE_DEFAULT, ROW_STYLE_VALUE1, ROW_STYLE_VALUE2, ROW_STYLE_SUBTITLE as per Apple Documentation on Native Cell Style support. for Value1 and Value2, we could also use the subtitle parameter or have a label2 parameter where we could pass a label view. There is a community request for that on: http://developer.appcelerator.com/question/45281/any-planned-support-for-iphone-native-table-cell-styles Apple Reference on Native Cell Styles: http://developer.apple.com/library/ios/documentation/uikit/reference/UITableViewCell_Class/Reference/Reference.html#//apple_ref/c/tdef/UITableViewCellStyle