Load resources from framework

[scinfu]

If this library is linked into a framework all resources will not be found ,the right way to load images is to use this api
imageNamed:(NSString *) inBundle:(NSBundle *) compatibleWithTraitCollection:(UITraitCollection *)
but is supported only in iOS8 .

I fix this issue using [[NSBundle bundleForClass:[self class]]resourcePath]>

[allaire]

@scinfu Was the "2x" if really required?

Might be cleaner to do:

UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfFile:imagePath] scale:[UIScreen mainScreen].scale];

[allaire]

Just opened a new PR with less code, it loads retina images correctly: #131