[TIMOB-12643] iOS: TableView selectRow method is moving TableView to the middle

*Problem* Method selectRow of Ti.UI.TableView centers the selected row to the middle of the screen. *Test Code*

var win = Ti.UI.createWindow();

var data = [];
for (var i = 0; i < 150; i++) {
	data.push( { title: "Foobar " + i } );
}

var tableView = Ti.UI.createTableView({
	data: data
});
win.add(tableView);

tableView.addEventListener("click", function(e) {
	// Here, the TableView is scrolling to the center 
	// of TableViewRow selected.
	this.selectRow( e.index );
});

win.open();

It happens because of selectRow method in iOS Class (TiUITableView.m at line 2051) the parameter *atScrollPosition* is UITableViewScrollPositionMiddle. *Requested Change* IMHO, what need to happens: 1) When TableViewRow isn't visible (100%) at the top, it needs to be scrolled to the top, using UITableViewScrollPositionTop. 2) When TableViewRow isn't visible (100%) at the bottom, it needs to be scrolled to the bottom, using UITableViewScrollPositionBottom. 3) When TableViewRow is complete visible, it doesn't needs to be scrolled to anywhere, using UITableViewScrollPositionNone. *Or* Allow developers to "force" scrollPosition with a second parameter of *selectRow*, using constants like "top", "bottom", "middle" or "none". *Note* Tested selectRow on Android (4.1.1) and seems to be broken. Use the same test code above on Android OS and rows are not selected, rather when a row is clicked, the tableView just scrolls down.