[DEV] open new 1.6 development branch

This new branch is based on 1.5.0, which 1.6-dev0 is 100% equivalent to.
The README has been updated to mention that it is a development branch.

Released version 1.6-dev0 with the following main changes :
    - exact copy of 1.5.0
diff --git a/README b/README
index 424a1f8..bf9e82b 100644
--- a/README
+++ b/README
@@ -1,7 +1,7 @@
                          ----------------------
                              HAProxy how-to
                          ----------------------
-                               version 1.5
+                             version 1.6-dev
                              willy tarreau
                                2014/06/19
 
@@ -9,12 +9,14 @@
 1) How to build it
 ------------------
 
-First, please note that this version is a stable version, so in general if you
-are not used to build from sources, it is recommended that instead you follow
-the packaged updates provided by your software vendor or Linux distribution.
-Most of them are taking this task seriously and are doing a good job. If for
-any reason you'd prefer a different version than the one packaged for your
-system, or to get some commercial support, other choices are available at :
+First, please note that this version is a development version, so in general if
+you are not used to build from sources or if you don't have the time to track
+very frequent updates, it is recommended that instead you switch to the stable
+version (1.5) or follow the packaged updates provided by your software vendor
+or Linux distribution. Most of them are taking this task seriously and are
+doing a good job. If for any reason you'd prefer a different version than the
+one packaged for your system, or to get some commercial support, other choices
+are available at :
 
                         http://www.haproxy.com/