[#73] Avoid String creation using system default charset

Used `StandardCharsets.UTF_8` to create `String` in `JSONParserByteArray` to avoid dependency on system's default charset

json-smart/src/main/java/net/minidev/json/parser/JSONParserByteArray.java

@@ -19,6 +19,9 @@
 import net.minidev.json.JSONValue;
 import net.minidev.json.writer.JsonReaderI;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
 /**
  * Parser for JSON text. Please note that JSONParser is NOT thread-safe.
  * 
@@ -59,7 +62,7 @@ public <T> T parse(byte[] in, JsonReaderI<T> mapper) throws ParseException {
 	}
 
 	protected void extractString(int beginIndex, int endIndex) {
-		xs = new String(in, beginIndex, endIndex - beginIndex);
+		xs = new String(in, beginIndex, endIndex - beginIndex, StandardCharsets.UTF_8);
 	}
 
 	protected void extractStringTrim(int start, int stop) {
@@ -71,7 +74,7 @@ protected void extractStringTrim(int start, int stop) {
 		while ((start < stop) && (val[stop - 1] <= ' ')) {
 			stop--;
 		}
-		xs = new String(in, start, stop - start);
+		xs = new String(in, start, stop - start, StandardCharsets.UTF_8);
 	}
 
 	protected int indexOf(char c, int pos) {