add some features for EJBindingAdBanner

[finscn]

adBanner.alwaysPortrait : if true force the iAd to be Portrait mode, or iAd to be auto mode
adBanner.isAtRight: if use "Portrait iAd" in Landscape device, let ad align to right

adBanner.x : get/set Position X
adBanner.y : get/set Position Y

adBanner.width (readOnly) return the adBanner's real size ( banner.frame's size)
adBanner.height (readOnly) return the adBanner's real size ( banner.frame's size)

[finscn]

this pull request is for #350

[finscn]

in iOS 6 later, Apple supplies a new Ad type:
ADAdTypeMediumRectangle ( iPad only)

I integrated it in ejecta like this:

// type="rect", "rectangle" "MediumRectangle" will use ADAdTypeMediumRectangle.
// other value will use ADAdTypeBanner
new Ejecta.AdBanner( type )

[finscn]

the String argument is ugly , maybe create a function for Rect-iAd is a better way.

Ejecta.AdPanel=function(){
return new Ejecta.AdBanner( "rectangle" )
}
new Ejecta.AdPanel();

[finscn]

@phoboslab , my game has use this one, I think its no problem.
Could you merge it ?

You can see it in Beside You ( the iAd only displayed in Pause Page and Help Page)
Though, the fill rate of iAd is not 100% , so you couldn't see the iAd every time.

in my case , I used

       var iAd = new Ejecta.AdBanner();
       iAd.alwaysPortrait = true;
       iAd.isAtBottom = false;
       iAd.isAtRight = false;