Kickstart a new rewrite of the raidillon engine

Endless refactors, refactor everyday, refactor relentlessly, refactor
every morning, every day, every hour.

raidillon_platform/src/event.rs

@@ -0,0 +1,11 @@
+pub enum PlatformEvent {
+    /// Emmited when the window should
+    RedrawRequested,
+
+    /// The platform has requested to close the app.
+    CloseRequested,
+    
+    /// Platform event loop is about to block and wait for new
+    /// new events.
+    AboutToWait
+}