added changelog

Author: Mark

ChangeLog

@@ -1,3 +1,15 @@
+v4.1.8 (2017-02-xx)
+---------------------------
+* changed java.util.Date serialization from VPack.date to VPack.string (ISO 8601)
+* changed java.sql.Date serialization from VPack.date to VPack.string (ISO 8601)
+* changed java.sql.Timestamp serialization from VPack.date to VPack.string (ISO 8601)
+* changed java.java.time.Instant serialization from VPack.date to VPack.string (ISO 8601)
+* changed java.java.time.LocalDate serialization from VPack.date to VPack.string (ISO 8601)
+* changed java.java.time.LocalDateTime serialization from VPack.date to VPack.string (ISO 8601)
+* added byte[] de-/serialization from/to VPack.string (Base64)
+* added ArangoCollection.drop(isSystem)
+* improved ArangoDBException with responseCode, errorNum, errorMessage
+
 v4.1.7 (2017-01-26)
 ---------------------------
 * fixed importDocuments, insertDocuments to work with raw Jsons (issue #91)