require gnu make for manpages

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

README

@@ -107,7 +107,7 @@ To install cdist, execute the following commands:
     cd cdist
     export PATH=$PATH:$(pwd -P)/bin
 
-    # If you want the manpages (requires asciidoc to be installed)
+    # If you want the manpages (requires gmake and asciidoc to be installed)
     make man
     export MANPATH=$MANPATH:$(pwd -P)/doc/man
 
@@ -136,7 +136,7 @@ may vanish at any point. To select a specific branch use
     git checkout -b <name> origin/<name>
     
     # Stay on a specific version
-    git checkout -b 1.3 origin/1.3
+    git checkout -b 1.4 origin/1.4
 
 ### Mirrors