clean up workspaces a little

substrate/runtime-std/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "runtime-std"
+version = "0.1.0"
+authors = ["Robert Habermeier <rphmeier@gmail.com>"]
+
+[dependencies]

substrate/runtime-std/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}