[TIMOB-14011] Added isLandscape, isPortrait, isFaceDown, and isFaceUp 

Sample code:
```
var win = Titanium.UI.createWindow({
    orientationModes: [Ti.UI.LANDSCAPE_LEFT, Ti.UI.LANDSCAPE_RIGHT, Ti.UI.PORTRAIT]
});

var btn = Ti.UI.createButton({
    title: 'orientation test'
});

btn.addEventListener('click', function(){
    if(Ti.Gesture.isPortrait()) {
        alert('is portrait');
    } else if(Ti.Gesture.isLandscape()){
        alert('is landscape');
    } else if(Ti.Gesture.isFaceUp()){
        alert('is face up');
    } else if(Ti.Gesture.isFaceDown()){
        alert('is face down');
    } else {
        alert('is unknown');
    }
});

win.add(btn);

win.open();
```