Updated Material2DAnimationSpec

It's now possible to provide a second easing curve to handle
interpolations for the 3rd and 4th variable.

This is usefuld for example when interpolating bounds, where the first
two variables may correpond to the location and the last two variables
correspond to the dimensions and you may want different easing curves
for each pair.

Author: oscar-ad

demoProjects/Drag2DCompose/app/src/main/java/android/support/drag2d/Material2DMotionPreview.kt

@@ -16,7 +16,7 @@
 
 package android.support.drag2d
 
-import android.support.drag2d.compose.Material2DAnimationSpec
+import android.support.drag2d.compose.materialVelocity2D
 import android.support.drag2d.lib.MaterialEasing
 import android.support.drag2d.lib.MaterialVelocity
 import androidx.compose.animation.core.Animatable
@@ -144,10 +144,9 @@ fun Material2DMotionPreview() {
                                     touchUpIndex.value = accumulator.size - 1
                                     val initialVelocity = velocityTracker.calculateVelocity()
 
-                                    // Velocity tracker has a tendency to fail measuring velocity
                                     offset.animateTo(
                                         targetValue = Offset.Zero,
-                                        animationSpec = Material2DAnimationSpec(
+                                        animationSpec = materialVelocity2D(
                                             duration.value.roundToInt(),
                                             maxVelocity.value,
                                             maxAcceleration.value,