impl Repo and md5-cache reading

tests/repo.rs

@@ -0,0 +1,10 @@
+use gentoo_utils::ebuild::repo::Repo;
+
+#[test]
+fn test_read_repo() {
+    let repo = Repo::new("/var/db/repos/gentoo");
+
+    for category in repo.categories().unwrap().map(|cat| cat.unwrap()) {
+        for _ in category.ebuilds().unwrap().map(|ebuild| ebuild.unwrap()) {}
+    }
+}