[TIMOB-18769] ImageView.hires does not work for @3x

The following code:

<ImageView image="http://dev.fokkezb.nl/image@3x.png" hires="true" />

Will not display the 300px wide image at the expected 100dp width, but instead at 150dp. The following 2 code fragments need fixing: * https://github.com/appcelerator/titanium_mobile/blob/9b02f6324fb09f28fc79d29e294c92949c7d0859/iphone/Classes/TiUIImageView.m#L491-L492 * https://github.com/appcelerator/titanium_mobile/blob/afc36d4f421424dc1ef6d618201f43616bb7857b/iphone/Classes/UIImage%2BResize.m#L30 They both should use the device logicalDensityFactor instead of the hard-coded 2.