Improvements to multi select

* selection bar now uses an <- instead of X icon
* FAB animates away when entering either selection or search mode
* allow selection mode to be entered once already in search mode

Demo: https://drive.google.com/a/google.com/file/d/0B-vjphxTdjuANERMUDF6Y2NyQXc/view?usp=sharing

Bug: 19549465
Change-Id: I657bf564c8e6cdfca6f7779918c4807e09e78d9b
diff --git a/res/layout/floating_action_button.xml b/res/layout/floating_action_button.xml
index 1541d42..294d88b 100644
--- a/res/layout/floating_action_button.xml
+++ b/res/layout/floating_action_button.xml
@@ -22,6 +22,7 @@
     android:layout_height="@dimen/floating_action_button_height"
     android:layout_marginEnd="@dimen/floating_action_button_margin_right"
     android:layout_marginBottom="@dimen/floating_action_button_margin_bottom"
+    android:background="@drawable/fab_blue"
     android:layout_alignParentEnd="true"
     android:layout_alignParentBottom="true">