[orx-keyframer] Add DoubleArrayChannel

orx-keyframer/src/main/kotlin/Keyframer.kt

@@ -18,7 +18,6 @@ import kotlin.reflect.KProperty1
 import kotlin.reflect.full.memberProperties
 import kotlin.reflect.jvm.isAccessible
 
-
 enum class KeyframerFormat {
     SIMPLE,
     FULL
@@ -97,6 +96,18 @@ open class Keyframer {
                 ColorRGBa(getValue(0), getValue(1), getValue(2))
     }
 
+    inner class DoubleArrayChannel(keys: Array<String>, defaultValue: DoubleArray = DoubleArray(keys.size)) :
+            CompoundChannel(keys, defaultValue.toTypedArray()) {
+        operator fun getValue(keyframer: Keyframer, property: KProperty<*>): DoubleArray {
+            val result = DoubleArray(keys.size)
+            for (i in keys.indices) {
+                result[i] = getValue(i)
+            }
+            return result
+        }
+    }
+
+
     val channels = mutableMapOf<String, KeyframerChannel>()
 
     fun loadFromJson(