Overhaul the Platformer Physics System

* Player character now experiences acceleration and friction when
  walking around the map!
* Actor position and movement had to be converted from int's
  (render.Point) to float64's to support fine-grained acceleration
  steps.
* Added "physics" package and physics.Vector to be a float64 counterpart
  for render.Point. Vector is used for uix.Actor.Position() for the sake
  of movement math. Vector is flattened back to a render.Point for
  collision purposes, since the levels and hitboxes are pixel-bound.
* Refactor the uix.Actor to no longer extend the doodads.Drawing (so it
  can have a Position that's a Vector instead of a Point). This broke
  some code that expected `.Doodad` to directly reference the
  Drawing.Doodad: now you had to refer to it as `a.Drawing.Doodad` which
  was ugly. Added convenience method .Doodad() for a shortcut.
* Moved functions like GetBoundingRect() from doodads package to
  collision, where it uses its own slimmer Actor interface for just the
  relevant methods it needs.

dev-assets/doodads/azulian/azulian-red.js

@@ -1,5 +1,5 @@
 function main() {
-	log.Info("Azulian '%s' initialized!", Self.Doodad.Title);
+	log.Info("Azulian '%s' initialized!", Self.Doodad().Title);
 
 	var playerSpeed = 4;
 	var gravity = 4;
@@ -28,8 +28,10 @@ function main() {
 		}
 		sampleTick++;
 
-		var Vx = playerSpeed * (direction === "left" ? -1 : 1);
+		// TODO: Vector() requires floats, pain in the butt for JS,
-		Self.SetVelocity(Point(Vx, 0));
+		// the JS API should be friendlier and custom...
+		var Vx = parseFloat(playerSpeed * (direction === "left" ? -1 : 1));
+		Self.SetVelocity(Vector(Vx, 0.0));
 
 		if (!Self.IsAnimating()) {
 			Self.PlayAnimation("walk-"+direction, null);

dev-assets/doodads/buttons/button.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	var timer = 0;
 
@@ -28,7 +28,7 @@ function main() {
 	});
 
 	// Events.OnLeave(function(e) {
-	// 	console.log("%s has stopped touching %s", e, Self.Doodad.Title)
+	// 	console.log("%s has stopped touching %s", e, Self.Doodad().Title)
 	// 	Self.Canvas.SetBackground(RGBA(0, 0, 1, 0));
 	// })
 }

dev-assets/doodads/buttons/sticky.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	var pressed = false;
 

dev-assets/doodads/doors/colored-door.js

@@ -1,6 +1,6 @@
 
 function main() {
-	var color = Self.Doodad.Tag("color");
+	var color = Self.Doodad().Tag("color");
 	var keyname = "key-" + color + ".doodad";
 
 	// Layers in the doodad image.

dev-assets/doodads/doors/electric-door.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	Self.AddAnimation("open", 100, [0, 1, 2, 3]);
 	Self.AddAnimation("close", 100, [3, 2, 1, 0]);
@@ -9,7 +9,7 @@ function main() {
 	Self.SetHitbox(16, 0, 32, 64);
 
 	Message.Subscribe("power", function(powered) {
-		console.log("%s got power=%+v", Self.Doodad.Title, powered);
+		console.log("%s got power=%+v", Self.Doodad().Title, powered);
 
 		if (powered) {
 			if (animating || opened) {

dev-assets/doodads/doors/keys.js

@@ -1,9 +1,9 @@
 function main() {
-	var color = Self.Doodad.Tag("color");
+	var color = Self.Doodad().Tag("color");
 
 	Events.OnCollide(function(e) {
 		if (e.Settled) {
-			e.Actor.AddItem(Self.Doodad.Filename, 0);
+			e.Actor.AddItem(Self.Doodad().Filename, 0);
 			Self.Destroy();
 		}
 	})

dev-assets/doodads/doors/locked-door.js

@@ -2,7 +2,7 @@
 function main() {
 	Self.AddAnimation("open", 0, [1]);
 	var unlocked = false;
-	var color = Self.Doodad.Tag("color");
+	var color = Self.Doodad().Tag("color");
 
 	Self.SetHitbox(16, 0, 32, 64);
 

dev-assets/doodads/mischievous.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	console.log(Object.keys(console));
 	console.log(Object.keys(log));

dev-assets/doodads/objects/exit-flag.js

@@ -1,6 +1,6 @@
 // Exit Flag.
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 	Self.SetHitbox(22+16, 16, 75-16, 86);
 
 	Events.OnCollide(function(e) {

dev-assets/doodads/on-off/state-button.js

@@ -4,7 +4,7 @@
 var state = false;
 
 function main() {
-	console.log("%s ID '%s' initialized!", Self.Doodad.Title, Self.ID());
+	console.log("%s ID '%s' initialized!", Self.Doodad().Title, Self.ID());
 	Self.SetHitbox(0, 0, 33, 33);
 
 	// When the button is activated, don't keep toggling state until we're not

dev-assets/doodads/switches/switch.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	// Switch has two frames:
 	// 0: Off

dev-assets/doodads/trapdoors/down.js

@@ -1,5 +1,5 @@
 function main() {
-	console.log("%s initialized!", Self.Doodad.Title);
+	console.log("%s initialized!", Self.Doodad().Title);
 
 	var timer = 0;
 

dev-assets/doodads/trapdoors/trapdoor.js

@@ -1,6 +1,6 @@
 function main() {
 	// What direction is the trapdoor facing?
-	var direction = Self.Doodad.Tag("direction");
+	var direction = Self.Doodad().Tag("direction");
 	console.log("Trapdoor(%s) initialized", direction);
 
 	var timer = 0;