feat(architecture): figure out ownership model

There is a central `YouTube` type which helps constructing various
sub-builders, which in turn provide individual functions.

Architecturally, it's very similar to the go implementation, but
more efficient memory wise.

src/common.rs

@@ -0,0 +1,28 @@
+/// Identifies the an OAuth2 authorization scope.
+/// A scope is needed when requesting an
+/// [authorization token](https://developers.google.com/youtube/v3/guides/authentication).
+pub enum Scope {
+    /// Manage your YouTube account
+    Account,
+    /// View your YouTube account
+    AccountReadOnly,
+    /// Manage your YouTube videos, which includes uploads and meta-data changes
+    Video,
+    /// View and manage your assets and associated content on YouTube
+    Partner,
+    /// View private information of your YouTube channel relevant during the
+    /// audit process with a YouTube partner.
+    Audit,
+}
+
+impl Str for Scope {
+    fn as_slice(&self) -> &str {
+        match *self {
+            Scope::Account => "https://www.googleapis.com/auth/youtube",
+            Scope::AccountReadOnly => "https://www.googleapis.com/auth/youtube.readonly",
+            Scope::Video => "https://www.googleapis.com/auth/youtube.upload",
+            Scope::Partner => "https://www.googleapis.com/auth/youtubepartner",
+            Scope::Audit => "https://www.googleapis.com/auth/youtubepartner-channel-audit",
+        }
+    }
+}

src/videos.rs

@@ -0,0 +1,35 @@
+use std::cell::RefCell;
+use std::borrow::BorrowMut;
+use std::marker::PhantomData;
+
+use hyper;
+
+pub struct VideosService<'a, C, NC>
+    where NC: 'a,
+           C: 'a {
+
+    client: &'a RefCell<C>,
+
+    _m: PhantomData<NC>
+}
+
+impl<'a, C, NC> VideosService<'a, C, NC>
+    where  NC: hyper::net::NetworkConnector,
+            C: BorrowMut<hyper::Client<NC>> + 'a {
+
+    pub fn new(client: &'a RefCell<C>) -> VideosService<'a, C, NC> {
+        VideosService {
+            client: client,
+            _m: PhantomData,
+        }
+    }
+}
+
+
+
+#[cfg(test)]
+mod tests {
+
+
+
+}