Set version to 4.0

CHANGES

diff --git a/CHANGES b/CHANGES
index 2cb26dc..15ff761 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,8 +1,9 @@
 i2c-tools CHANGES
 -----------------
 
-SVN HEAD
+4.0 (2017-10-30)
   tools: Fix build with recent compilers (gcc 4.6+)
+         Add examples to the manual pages
   README: Clarify licenses
           Mention the current maintainer
   decode-dimms: Decode module configuration type of DDR2 SDRAM

version.h

diff --git a/version.h b/version.h
index 549a790..073379b 100644
--- a/version.h
+++ b/version.h
@@ -1 +1 @@
-#define VERSION "3.1.0"
+#define VERSION "4.0"