Refactor FolderIcon to separate the preview effect into it's own class

-> Created com.android.launcher3.folder package to house most folder-related files
   (aside from the FolderInfo) which is more related to the model than the UI.

Change-Id: I767063e1e4c775c01a799a3bede30cd94ac48ade
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 7109895..c826c5f 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -343,7 +343,7 @@
     int getViewportWidth() {
         return mViewport.width();
     }
-    int getViewportHeight() {
+    public int getViewportHeight() {
         return mViewport.height();
     }
 
@@ -392,7 +392,7 @@
         return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
     }
 
-    int getPageCount() {
+    public int getPageCount() {
         return getChildCount();
     }
 
@@ -2020,7 +2020,7 @@
         snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION);
     }
 
-    protected void snapToPageImmediately(int whichPage) {
+    public void snapToPageImmediately(int whichPage) {
         snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION, true, null);
     }