Initial Commit

The initial commit of gnome-image-viewer.
Things are in an MVP state, with image viewing and
opening from the desktop functional. We also can
open images externally, print them, and set them as
backgrounds.

src/config.rs.in

@@ -0,0 +1,5 @@
+pub const APP_ID: &str = "@APP_ID@";
+pub const PROFILE: &str = "@PROFILE@";
+pub const PKGDATADIR: &str = "@pkgdatadir@";
+pub const VERSION: &str = "@VERSION@";
+pub const LOCALEDIR: &str = "@localedir@";