[TIMOB-5516] MobileWeb: Incorrect paddings in Button object

Incorrect paddings in Button object. When width of the button is small the align of the title is not center.

var win = Ti.UI.currentWindow;
win.backgroundColor = '#EEE';

var b1 = Ti.UI.createButton({
	title: 'Button',
	top: 10,
	left: 10,
	height: 40,
	width: 47,
	backgroundColor: '#888'
});

win.add(b1);

Expected behavior: title of the button should be in the center of the button. Actual result: space between left border of button and first letter of title is bigger than space between last letter of title and right border of button.