fixed for travis ci config file

.travis.yml

@@ -2,7 +2,7 @@ language: cpp
 compiler:
   - gcc
 before_install:
-    - sudo add-apt-repository ppa:texlive-backports/ppa -qq
+    - sudo add-apt-repository ppa:texlive-backports/ppa -y
     - sudo apt-get update -qq
     - sudo apt-get install -qq  texlive texlive-extra-utils texlive-latex-extra libxml2-utils
     - wget -qO- http://www.cmake.org/files/v3.1/cmake-3.1.0-Linux-x86_64.tar.gz | tar xvz