twrpDigest refactor

This patch is to refactor twrpDigest using polymorphism
and inheritance to use the same call patterns for creating and
reading a digest. Now a library.
Use SHA2 from libcrypto. SHA2 is default if device has libcrypto.

Change string MD5 everywhere to use digest or Digest instead. Updated
string tags to digest. Translation will be required.

Switch out digest code into a driver class from partitionmanager.

SHA2 is better for digest creation due to decreased collision space
compared to MD5 and SHA1.


Change-Id: I74b5546789990b12aa4ce2e389d25f80a3fe213f
diff --git a/twrpDigestDriver.hpp b/twrpDigestDriver.hpp
new file mode 100644
index 0000000..6902c8e
--- /dev/null
+++ b/twrpDigestDriver.hpp
@@ -0,0 +1,33 @@
+        Copyright 2013 to 2017 TeamWin
+        This file is part of TWRP/TeamWin Recovery Project.
+        TWRP is free software: you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation, either version 3 of the License, or
+        (at your option) any later version.
+        TWRP is distributed in the hope that it will be useful,
+        but WITHOUT ANY WARRANTY; without even the implied warranty of
+        GNU General Public License for more details.
+        You should have received a copy of the GNU General Public License
+        along with TWRP.  If not, see <>.
+#include <string>
+#include "twrpDigest/twrpDigest.hpp"
+class twrpDigestDriver {
+	static bool Check_Restore_File_Digest(const string& Filename);		//Check the digest of a TWRP partition backup
+	static bool Check_Digest(string Full_Filename);				//Check to make sure the digest is correct
+	static bool Write_Digest(string Full_Filename);				//Write the digest to a file
+	static bool Make_Digest(string Full_Filename);				//Create the digest for a partition backup
+	static bool stream_file_to_digest(string filename, twrpDigest* digest); //Stream the file to twrpDigest