diff --git a/.travis.yml b/.travis.yml
index a99f6b66077..4d98d56fe62 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,8 @@
 language: cpp 
 dist: trusty 
 sudo: required 
+git: 
+ depth: 3
 matrix:
  include: 
   - compiler: gcc 
@@ -95,8 +97,6 @@ matrix:
     env: PACKAGE='Triangulation_2 Triangulation_3 Union_find ' 
   - compiler: clang-3.6
     env: PACKAGE='Visibility_2 Voronoi_diagram_2 wininst ' 
-  - compiler: clang-3.6
-    env: PACKAGE='Polyhedron_demo' 
 install: 
   - bash .travis/install.sh 
   - if [[ "$CXX" = "clang++" ]]; then export CXX=clang++-3.6 CC=clang-3.6; fi
@@ -110,7 +110,6 @@ before_script:
 - make 
 - sudo make install &>/dev/null
 - cd ..
-- sudo bash ./.travis/install_openmesh.sh
 script: 
 - cd ./.travis
 - bash -x -e ./build_package.sh $PACKAGE
@@ -118,3 +117,4 @@ notifications:
   email:
     on_success: change # default: always
     on_failure: always # default: always
+
diff --git a/.travis/build_package.sh b/.travis/build_package.sh
index 680c94adf18..b034ad595ce 100755
--- a/.travis/build_package.sh
+++ b/.travis/build_package.sh
@@ -54,6 +54,15 @@ NEED_3D=0
 cd $ROOT
 for ARG in $(echo "$@")
 do
+#install openmesh only if necessary
+  if [ "$ARG" = "CHECK" ] || [ "$ARG" = BGL ] || [ "$ARG" = Convex_hull_3 ] ||\
+     [ "$ARG" = Polygon_mesh_processing ] || [ "$ARG" = Property_map ] ||\
+     [ "$ARG" = Surface_mesh_deformation ] || [ "$ARG" = Surface_mesh_shortest_path ] ||\
+     [ "$ARG" = Surface_mesh_simplification ]; then
+    sudo bash .travis/install_openmesh.sh
+  fi
+
+
   if [ "$ARG" = "CHECK" ]
   then
     cd .travis
@@ -118,6 +127,7 @@ do
     exit 0
   fi
   IFS=$old_IFS
+
   if [ -n "$TRAVIS_PULL_REQUEST" ] && [ "$ARG" != Polyhedron_demo ]; then
     DO_IGNORE=FALSE
     . $ROOT/.travis/test_package.sh "$ROOT" "$ARG"
diff --git a/.travis/generate_travis.sh b/.travis/generate_travis.sh
index 7c65175182b..e73f2ed9a5a 100755
--- a/.travis/generate_travis.sh
+++ b/.travis/generate_travis.sh
@@ -59,8 +59,8 @@ do
 echo "  - compiler: clang-3.6" >> .travis.yml
 echo "    env: PACKAGE='$package' " >> .travis.yml
 done
-echo "  - compiler: clang-3.6" >> .travis.yml
-echo "    env: PACKAGE='Polyhedron_demo' " >> .travis.yml
+#echo "  - compiler: clang-3.6" >> .travis.yml
+#echo "    env: PACKAGE='Polyhedron_demo' " >> .travis.yml
 
 #writes the end of the file
 COPY=0
@@ -75,6 +75,7 @@ do
 		echo "$LINE" >> .travis.yml
 	fi
 done
+echo "" >> .travis.yml
 IFS=$' '
 #check if there are differences between the files
 if ! cmp -s ./.travis.yml ./.travis.old;
diff --git a/.travis/install.sh b/.travis/install.sh
index e3dfe9dbb4e..161977c29f2 100644
--- a/.travis/install.sh
+++ b/.travis/install.sh
@@ -12,12 +12,13 @@ do
   DONE=1 && sudo -E apt-add-repository -y "ppa:hedges/qt5.5" ||  DONE=0 && sleep 5
 done
 
-for pkg in clang-3.6 zsh flex bison cmake graphviz libboost1.55-dev libboost-system1.55-dev libboost-program-options1.55-dev libboost-thread1.55-dev libboost-iostreams1.55-dev libgmp-dev libmpfr-dev libmpfi-dev zlib1g-dev libeigen3-dev qt55base qt55script qt55svg qt55tools qt55graphicaleffects libopencv-dev mesa-common-dev libmetis-dev libglu1-mesa-dev
+DONE=0
+while [ $DONE = 0 ]
 do
-  DONE=0
-  while [ $DONE = 0 ]
-  do
-    DONE=1 && sudo -E apt-get -yq --no-install-suggests --no-install-recommends --force-yes install $pkg || DONE=0 && sudo apt-get update
-  done
+  DONE=1 && sudo -E apt-get -yq --no-install-suggests --no-install-recommends --force-yes install clang-3.6 zsh \
+flex bison cmake graphviz libgmp-dev libmpfr-dev libmpfi-dev zlib1g-dev libeigen3-dev  libboost1.55-dev \
+libboost-system1.55-dev libboost-program-options1.55-dev libboost-thread1.55-dev libboost-iostreams1.55-dev \
+qt55base qt55script qt55svg qt55tools qt55graphicaleffects libopencv-dev mesa-common-dev libmetis-dev libglu1-mesa-dev \
+|| DONE=0 && sudo apt-get update
 done
 
diff --git a/.travis/template.txt b/.travis/template.txt
index 32ef77d336e..73b73bd2407 100644
--- a/.travis/template.txt
+++ b/.travis/template.txt
@@ -1,6 +1,8 @@
 language: cpp 
 dist: trusty 
 sudo: required 
+git: 
+ depth: 3
 matrix:
  include:
   PACKAGES_MATRIX
@@ -17,7 +19,6 @@ before_script:
 - make 
 - sudo make install &>/dev/null
 - cd ..
-- sudo bash ./.travis/install_openmesh.sh
 script: 
 - cd ./.travis
 - bash -x -e ./build_package.sh $PACKAGE
@@ -25,3 +26,4 @@ notifications:
   email:
     on_success: change # default: always
     on_failure: always # default: always
+
diff --git a/Scripts/developer_scripts/cgal_check_dependencies.sh b/Scripts/developer_scripts/cgal_check_dependencies.sh
index 2bb62a19a21..20c98b4b138 100644
--- a/Scripts/developer_scripts/cgal_check_dependencies.sh
+++ b/Scripts/developer_scripts/cgal_check_dependencies.sh
@@ -35,7 +35,7 @@ for pkg_path in $CGAL_ROOT/*
 do
   pkg=$(basename $pkg_path)
   if [ -f "$pkg_path/package_info/$pkg/dependencies" ]; then
-    PKG_DIFF=$(diff -N -w  "$pkg_path/package_info/$pkg/dependencies.old" "$pkg_path/package_info/$pkg/dependencies")
+    PKG_DIFF=$(diff -N -w  "$pkg_path/package_info/$pkg/dependencies.old" "$pkg_path/package_info/$pkg/dependencies" || true)
     if [ -n "$PKG_DIFF" ]; then
       HAS_DIFF=TRUE
       echo "Differences in $pkg: $PKG_DIFF"