FlxCamera with zoom fixed.

A single line of code was missing, found it after decompiling the FlxCameraDemo from the haxe website.

Now both ModeDemo and FlxCameraDemo work fine (like they used to).

Strange how that line disapeared, or maybe it was never commited before.

I am sending this pull request to dev branch, if any trouble occurs, i will buy the fattest git book availible (or send an email to chris explaining the problem may be easier).