Add minimizeModel to orx-gradient-descent

orx-gradient-descent/README.md

@@ -0,0 +1,36 @@
+# orx-gradient-descent
+
+A gradient descent based minimizer that is incredibly
+easy to use.
+
+## Usage
+
+```kotlin
+// define a model
+class Model {
+    var x = 0.0
+    var y = 0.0 
+}
+
+val model = Model()
+minimizeModel(model) { m ->
+    (m.x-4.0)*(m.x-4.0) + (m.y-3.0)*(m.y-3.0)
+}
+
+// model.x is close to 4 and model y is close to 3 at this point
+```
+
+## Data binding
+
+Currently we support minimizing model classes that contain 
+`Double`, `Vector2`, `Vector3` and `Vector4` typed properties, 
+other types are silently ignored.
+
+An example of a supported model:
+```kotlin
+class Model {
+    var x = 0.0
+    var y = 0.0
+    var v2 = Vector2.ZERO
+}
+```