Enable AddressSanitizer for Linux clang build

.travis.sh

@@ -1,6 +1,6 @@
 function generate()
 {
-    cmake -G "Unix Makefiles" -DASSIMP_NO_EXPORT=$TRAVIS_NO_EXPORT -DBUILD_SHARED_LIBS=$SHARED_BUILD -DASSIMP_COVERALLS=$ENABLE_COVERALLS
+    cmake -G "Unix Makefiles" -DASSIMP_NO_EXPORT=$TRAVIS_NO_EXPORT -DBUILD_SHARED_LIBS=$SHARED_BUILD -DASSIMP_COVERALLS=$ENABLE_COVERALLS -DASSIMP_ASAN=$ASAN
 }
 
 if [ $ANDROID ]; then

.travis.yml

@@ -28,13 +28,13 @@ env:
     - secure: "lZ7pHQvl5dpZWzBQAaIMf0wqrvtcZ4wiZKeIZjf83TEsflW8+z0uTpIuN30ZV6Glth/Sq1OhLnTP5+N57fZU/1ebA5twHdvP4bS5CIUUg71/CXQZNl36xeaqvxsG/xRrdpKOsPdjAOsQ9KPTQulsX43XDLS7CasMiLvYOpqKcPc="
     - PV=r8e PLATF=linux-x86_64 NDK_HOME=${TRAVIS_BUILD_DIR}/android-ndk-${PV} PATH=${PATH}:${NDK_HOME}
   matrix:
-    - os: linux LINUX=1 TRAVIS_NO_EXPORT=YES ENABLE_COVERALLS=ON
+    - os: linux LINUX=1 TRAVIS_NO_EXPORT=YES ENABLE_COVERALLS=ON  ASAN=OFF
       compiler: gcc
-    - os: linux LINUX=1 TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF
+    - os: linux LINUX=1 TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=ON
       compiler: clang
-    - os: linux LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF
+    - os: linux LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=OFF
       compiler: gcc
-    - os: linux LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF
+    - os: linux LINUX=1 SHARED_BUILD=ON TRAVIS_NO_EXPORT=NO  ENABLE_COVERALLS=OFF ASAN=OFF
       compiler: clang
     - os: osx
       osx_image: xcode8.2