New aapt feature to do smarter filtering of configurations.

This adds a --preferred-configurations flag that specifies the
specific configurations you would like to have.

It is smarter than "-c" because it will avoid stripping a
configuration if that would result in there being no value
for the resource.

It is dumber than "-c" because it can't process as many kinds
of resources.  It is really only intended for bitmaps and use
with density configs.

This required re-arranging AaptAssets to group files together
by config again, like they used to be.  I think this hasn't
broken anything.  Hopefully.

Change-Id: I4e9d12ff6e6dbd1abb8fd4cb1814c6674b19d0e5
diff --git a/tools/aapt/Command.cpp b/tools/aapt/Command.cpp
index 413a2dc..637c27d 100644
--- a/tools/aapt/Command.cpp
+++ b/tools/aapt/Command.cpp
@@ -5,6 +5,7 @@
 //
 #include "Main.h"
 #include "Bundle.h"
+#include "ResourceFilter.h"
 #include "ResourceTable.h"
 #include "XMLNode.h"
 
@@ -1572,7 +1573,7 @@
     }
 
     if (bundle->getVerbose()) {
-        assets->print();
+        assets->print(String8());
     }
 
     // If they asked for any fileAs that need to be compiled, do so.