[ashoksudani] : Making image path working with asset path created by rails asset pipeline.

Hi Martin.

While using the plugin with rails asset pipeline I cam across the limitation when we want to load image with asset path (including fingerprint for production env) created by rails asset pipeline for each image.

So rather than using [[display]] token in the path and replacing each one by currentDisplay I just pushed small one line change which would make choosing image completely independent from [[display]] token  and plugin would load image from defined attribute with display name for each matched media query.

I think this way it would get abstracted from dependency on only one image name with [[display]] token and we can put different image for different matched displays. 

This way it would work in both ways weather we are dependent or not on asset pipleline and make image name completely independent.

Thanks,
Ashok