add typedefs for forward compat

include/fc/crypto/sha256.hpp

@@ -65,6 +65,8 @@ class sha256
     uint64_t _hash[4]; 
 };
 
+  typedef sha256 uint256;
+
   class variant;
   void to_variant( const sha256& bi, variant& v );
   void from_variant( const variant& v, sha256& bi );

include/fc/crypto/sha512.hpp

@@ -65,6 +65,8 @@ class sha512
     uint64_t _hash[8]; 
 };
 
+  typedef fc::sha512 uint512;
+
   class variant;
   void to_variant( const sha512& bi, variant& v );
   void from_variant( const variant& v, sha512& bi );