Initial API structre

src/data/tasks.rs

@@ -0,0 +1,18 @@
+use uuid::Uuid;
+
+/// A to-do task
+pub struct Task {
+    id: Uuid,
+    name: String,
+}
+
+impl Task {
+    pub fn id(&self) -> Uuid        { self.id           }
+    pub fn name(&self) -> String    { self.name         }
+    pub fn completed(&self) -> bool { self.completed    }
+
+    pub fn set_completed(&mut self) {
+        // TODO: either require a reference to the DataSource, so that it is aware
+        //       or change a flag here, and the DataSource will be able to check the flags of all its content (but then the Calendar should only give a reference/Arc, not a clone)
+    }
+}