Fix travis and allow clang failures

.travis.yml

@@ -10,6 +10,7 @@ os:
 matrix:
   allow_failures:
     - os: osx
+    - compiler: clang
 addons:
   apt:
     packages:
@@ -18,10 +19,11 @@ install:
 - wget -O boost.tar.bz2 https://sourceforge.net/projects/boost/files/boost/1.56.0/boost_1_56_0.tar.bz2/download
 - tar -xf boost.tar.bz2
 - cd boost_1_56_0
+# TODO We should use clang as toolchain for building boost when clang is used for building our code
 - ./bootstrap.sh --with-libraries=filesystem,thread
 - sudo ./b2 -d0 install
 - cd ..
-- rm -rf boost.tar.bz2 boost_1_56_0
+- sudo rm -rf boost.tar.bz2 boost_1_56_0
 script:
 - mkdir cmake
 - cd cmake