updated and added new Utils (#9)

* added SeedRandomGenerator

* extended IotaUnitConverter

* minor

* added isArrayOfHashes

* renamed constants

* added error package

* added transactionObject

* fixed IotaUnitConverter

src/test/java/jota/SeedRandomGeneratorTest.java

@@ -0,0 +1,22 @@
+package jota;
+
+import jota.utils.Constants;
+import jota.utils.InputValidator;
+import jota.utils.SeedRandomGenerator;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Created by pinpong on 13.12.16.
+ */
+public class SeedRandomGeneratorTest {
+
+    @Test
+    public void shouldGenerateNewSeed() {
+
+        String generatedSeed = SeedRandomGenerator.generateNewSeed();
+        assertEquals(InputValidator.isAddress(generatedSeed), true);
+        assertEquals(generatedSeed.length(), Constants.SEED_LENGTH_MAX);
+    }
+}