add log_merge.sh script to generate per-testcase merged logs

Change-Id: Ife6153d2cc10f85e79e8df7a0e34a44648618976
diff --git a/Common.cfg b/Common.cfg
index 38beb5a..96f0687 100644
--- a/Common.cfg
+++ b/Common.cfg
@@ -6,6 +6,8 @@
 TCPDUMP_STOP := $TTCN3_HACKS_PATH"/ttcn3-tcpdump-stop.sh"
 
 [LOGGING]
+LogFile := "%e-%c-%h-%r.%s"
+AppendFile := Yes;
 SourceInfoFormat := Single;
 LogSourceInfo := Yes;
 LoggerPlugins := { JUnitLogger := "libjunitlogger2" }