#358 Add future interface methods, remove exception throwing

- Create Utils class for a common implementation of md5/sha1
- Create "foolproof" way of getting the MessageDigest for md5 etc. (MessageDigestAlgorithm enum)
- Create description annotations to annotate algorithms with usage recommendation and salt type

src/main/java/fr/xephi/authme/security/crypts/EncryptionMethod.java

@@ -32,4 +32,8 @@ public interface EncryptionMethod {
     boolean comparePassword(String hash, String password, String playerName)
         throws NoSuchAlgorithmException;
 
+    // String generateSalt();
+
+    // String computeHash(String password, String name);
+
 }