Fixed crash on Dupe Count sorting with Delta + Dupes Only

Fixes #238
Merge branch 'master' into develop
Fixed appdata logic which was broken on OS X.
On OS X, read Exif tags using Cocoa's built-in functionality

This allows for RAW files Exif reading. Fixes #234.
Fixed build on OS X which was broken
Fixed compilation warnings on OS X
Fixed tests which were broken
Merge branch 'develop' into path-refactor
Updated hscommon