Clarify Makefile instructions, remove me from explicit travis sender list

.travis.yml

@@ -10,7 +10,6 @@ branches:
 
 notifications:
   email:
-    - hanno@hannosch.eu
     - buildout-development@googlegroups.com
 
 install:

DEVELOPERS.txt

@@ -11,14 +11,17 @@ When you're developing buildout itself, you need to know two things:
   dev.py``.
 
 For your convenience we provide a Makefile to build various Python versions
-in subdirectories of the buildout checkout. To use this do::
+in subdirectories of the buildout checkout. To use these and run the tests
+with them do::
 
     make PYTHON_VER=2.6 build
-    make PYTHON_VER=2.7 build
-    make PYTHON_VER=3.2 build
-
-In order to run the tests, you can then use::
-
     make PYTHON_VER=2.6 test
+
+    make PYTHON_VER=2.7 build
     make PYTHON_VER=2.7 test
+
+    make PYTHON_VER=3.2 build
     make PYTHON_VER=3.2 test
+
+The actual Python compilation is only done once and then re-used. So on
+subsequent builds, only the development buildout itself needs to be redone.