Including a cause stacktrace in CreationException. Several people were complaining about the missing stacktraces, because their logging was configured to not display anything!

git-svn-id: https://google-guice.googlecode.com/svn/trunk@605 d779f126-a31b-0410-b53b-1d3aecad763e
diff --git a/src/com/google/inject/CreationException.java b/src/com/google/inject/CreationException.java
index f90c72c..799a3bc 100644
--- a/src/com/google/inject/CreationException.java
+++ b/src/com/google/inject/CreationException.java
@@ -38,6 +38,14 @@
    */
   public CreationException(Collection<? extends Message> errorMessages) {
     this.errorMessages = ImmutableList.copyOf(errorMessages);
+
+    // find a cause
+    for (Message message : errorMessages) {
+      if (message.getCause() != null) {
+        initCause(message.getCause());
+        break;
+      }
+    }
   }
 
   /**