try python again, 7 (ok, now manually)

.travis.yml

@@ -45,9 +45,16 @@ before_install:
   #- sudo apt-get install libc6-dbg
   #
   # python bindings runtime dependencies
+  - git clone https://github.com/atgreen/libffi
+  - cd libffi
+  - ./autogen.sh
+  - ./configure --prefix=/usr
+  - make
+  - sudo make install
+  - cd ..
   - sudo apt-get update -qq
-  - sudo apt-get install python-cffi 
-  #- sudo pip install cffi
+  - sudo apt-get install python-pip
+  - sudo pip install cffi
   #
   # finally prepare autoconf stuff
   - ./autogen.sh