Refactored code to use core::*

hash.rs

@@ -1,8 +1,6 @@
-use std;
+import core::ptr;
-
+import core::str;
-import std::ptr;
+import core::vec;
-import std::str;
-import std::vec;
 
 export hasher;
 export hashtype;

pkey.rs

@@ -1,9 +1,7 @@
-use std;
+import core::ptr;
-
+import core::str;
-import std::ptr;
+import core::unsafe;
-import std::str;
+import core::vec;
-import std::unsafe;
-import std::vec;
 
 export pkeyrole, encrypt, decrypt, sign, verify;
 export pkey, mk_pkey;

symm.rs

@@ -1,8 +1,6 @@
-use std;
+import core::ptr;
-
+import core::str;
-import std::ptr;
+import core::vec;
-import std::str;
-import std::vec;
 
 export crypter;
 export cryptermode;