Show/hide FloatingActionButton improvements

We now have an explicit show()/hide() method so that
developers can use the spec'd animation.

Also fixed an issue where the FAB would be animated in,
overriding the developers set vsibility.

BUG: 21652571
BUG: 21652427
BUG: 21689751

Change-Id: I248d49b812c018e6d46a6ccde262433868ae272e
diff --git a/design/api/current.txt b/design/api/current.txt
index 217ba99..9dc6e20 100644
--- a/design/api/current.txt
+++ b/design/api/current.txt
@@ -170,7 +170,9 @@
     ctor public FloatingActionButton(android.content.Context);
     ctor public FloatingActionButton(android.content.Context, android.util.AttributeSet);
     ctor public FloatingActionButton(android.content.Context, android.util.AttributeSet, int);
+    method public void hide();
     method public void setRippleColor(int);
+    method public void show();
   }
 
   public static class FloatingActionButton.Behavior extends android.support.design.widget.CoordinatorLayout.Behavior {