[MEDIUM] Decrease server health based on http responses / events, version 3

Implement decreasing health based on observing communication between
HAProxy and servers.

Changes in this version 2:
 - documentation
 - close race between a started check and health analysis event
 - don't force fastinter if it is not set
 - better names for options
 - layer4 support

Changes in this version 3:
 - add stats
 - port to the current 1.4 tree
diff --git a/include/common/defaults.h b/include/common/defaults.h
index b0aee86..cada729 100644
--- a/include/common/defaults.h
+++ b/include/common/defaults.h
@@ -120,6 +120,9 @@
 #define DEF_CHECK_REQ   "OPTIONS / HTTP/1.0\r\n\r\n"
 #define DEF_SMTP_CHECK_REQ   "HELO localhost\r\n"
 
+#define DEF_HANA_ONERR		HANA_ONERR_FAILCHK
+#define DEF_HANA_ERRLIMIT	10
+
 // X-Forwarded-For header default
 #define DEF_XFORWARDFOR_HDR	"X-Forwarded-For"