[Shotwell] hide raw+jpeg duplicates

[Alexey Fisher]

Hallo,
i just tested version 0.8. Thank you for the great work!

to make things better i have one wish: hide raw+jpeg duplicates. Modern
DSLR cameras can produce two file per one shot RAW and JPG. they are
easy to detect, they haw same name and creation time but different file
suffix. For example DSC_0020.JPG and DSC_0020.NEF

It make no sense to show both of them. You can hide it and make it
noticeable by adding some symbol under the image. Some thing like "more"
or "jpg/nef" 

This kind of duplicates you can find even on some point and shot
cameras. for example video and thumbnail. They have *always* same rule:
same name, different suffix.

-- 
Regards,
        Alexey