#792 Add columns for registration IP and registration date

- Add columns for reg date and IP
- Rename "ip" to "last IP"

src/main/java/fr/xephi/authme/datasource/SqlDataSourceUtils.java

@@ -2,6 +2,7 @@ package fr.xephi.authme.datasource;
 
 import fr.xephi.authme.ConsoleLogger;
 
+import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
@@ -20,4 +21,18 @@ final class SqlDataSourceUtils {
     static void logSqlException(SQLException e) {
         ConsoleLogger.logException("Error during SQL operation:", e);
     }
+
+    /**
+     * Returns the long value of a column, or null when appropriate. This method is necessary because
+     * JDBC's {@link ResultSet#getLong} returns {@code 0} if the entry in the database is {@code null}.
+     *
+     * @param rs the result set to read from
+     * @param columnName the name of the column to retrieve
+     * @return the value (which may be null)
+     * @throws SQLException :)
+     */
+    static Long getNullableLong(ResultSet rs, String columnName) throws SQLException {
+        long longValue = rs.getLong(columnName);
+        return rs.wasNull() ? null : longValue;
+    }
 }