Add single crunch command to aapt. do not merge.

Previously the crunch command would work on a full res folder
and output a full res folder (with only the drawables). This
was only used in the SDK.

The incremental logic is moved to the SDK build system so we
change the crunch command (or rather add a new one) to only
crunch a single file.

(cherry picked from commit b1f6ad82dd8d1702617a757a88430604b3131fac)

Change-Id: I3653f67ee321eac37cb8a6d228b1ef6d104ff0be
diff --git a/tools/aapt/Main.h b/tools/aapt/Main.h
index d20c601..a6b39ac 100644
--- a/tools/aapt/Main.h
+++ b/tools/aapt/Main.h
@@ -29,6 +29,7 @@
 extern int doRemove(Bundle* bundle);
 extern int doPackage(Bundle* bundle);
 extern int doCrunch(Bundle* bundle);
+extern int doSingleCrunch(Bundle* bundle);
 
 extern int calcPercent(long uncompressedLen, long compressedLen);