Add a library template for an Exif library.

Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "exif"
+version = "0.1.0"
+authors = ["KAMADA Ken'ichi <kamada@nanohz.org>"]

src/lib.rs

@@ -0,0 +1,6 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+    }
+}