Try another tactic for travis

.travis.yml

@@ -1,27 +1,29 @@
+sudo: false
 language: cpp
 
 before_install:    
     # Define TRAVIS variable for workarounds
     - export CXXFLAGS="$CXXFLAGS -DTRAVIS"
-    
-    - if [ "$CXX" == "g++" ]; then sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test; fi
-    - if [ "$CXX" == "clang++" ]; then sudo add-apt-repository -y ppa:h-rayflood/llvm; fi
     - sudo apt-get -qq update
     
     # Install dependencies
     - sudo apt-get -qq install libwxgtk3.0-dev libwxgtk3.0-0 libssh2-1-dev
 
 install:
-    - if [ "$CXX" = "g++" ]; then sudo apt-get install -qq g++-4.8; fi
     - if [ "$CXX" = "g++" ]; then sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 98; fi
 
-    #clang
-    - if [ "$CXX" == "clang++" ]; then sudo apt-get install --allow-unauthenticated -qq clang-3.4; fi
-    - if [ "$CXX" == "clang++" ]; then export CXX="clang++-3.4"; fi
-
 # Build with both gcc and clang
 compiler:
     - gcc
     - clang
     
+addons:
+    apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        packages:
+        - gcc-4.8
+        - g++-4.8
+        - clang
+
 script: make clean run-tests