Groundwork for exception support:

     Auto generate result structs that combine return type and any thrown exceptions
     Add __isset struct to all user defined and auto defined struct to mark fields that are explicilty read
     Modified client and server generation code to marshal result structs

     Added base facebook::thrift::Exception class 


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@664750 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/test/ThriftTest.thrift b/test/ThriftTest.thrift
index 2e88725..64c045a 100644
--- a/test/ThriftTest.thrift
+++ b/test/ThriftTest.thrift
@@ -31,6 +31,8 @@
   list<Xtruct> xtructList = 1
 }
 
+struct Empty {}
+
 service ThriftTest
 {
   void         testVoid()