Enable directory browsing

Extracting the appropriate globs from the MIME database.

fastiv.desktop

@@ -7,5 +7,5 @@ Exec=fastiv %F
 Terminal=false
 StartupNotify=true
 Categories=Graphics;2DGraphics;Viewer;
-# TODO(p): Figure out how to include RAW MIME types, if appropriate.
-MimeType=image/png;image/bmp;image/x-bmp;image/x-MS-bmp;image/gif;image/jpeg;
+# TODO(p): Generate this list from source files.
+MimeType=image/png;image/bmp;image/gif;image/jpeg;image/x-dcraw;