Check regex for validity before querying

Change-Id: I03bbefcecc2b51f8ca611a9453fd253dd972718e
diff --git a/Changes b/Changes
index fbede7d..dfd1dc6 100644
--- a/Changes
+++ b/Changes
@@ -1,4 +1,4 @@
-0.59.0 2019-11-27
+0.59.0 2019-11-28
     - [bugfix] Fix offset retrieval in concurrent searches
       (diewald)
     - [cleanup] Removed deprecated numberOf() method from index
@@ -9,6 +9,8 @@
       & libraries (margaretha)
     - [feature] Support for vector representation of terms in KoralQuery
       (diewald)
+    - [bugfix] Check regex for validity before querying
+      (diewald)
 
 0.58.7 2019-09-16
     - [bugfix] Fix the behaviour of negative operands in virtual