Replaced libsdl2-dev dependency by a direct download

.travis.yml

@@ -32,7 +32,7 @@ before_install:
     fi
 
 install:
-- sudo apt-get install --force-yes -qq libtinyxml-dev libjpeg-dev libpng-dev libgif-dev libz-dev libsdl2-dev libboost-system-dev libboost-thread-dev libboost-date-time-dev
+- sudo apt-get install --force-yes -qq libtinyxml-dev libjpeg-dev libpng-dev libgif-dev libz-dev libboost-system-dev libboost-thread-dev libboost-date-time-dev
 - if [ "$BUILD_PSP" == "YES" ]; then
     tar -x --xz -f sdk.lzma;
   fi
@@ -41,6 +41,10 @@ install:
     tar -zxf android-sdk_r24.3.3-linux.tgz &&
     $ANDROID list sdk --extended -a &&
     echo yes | $ANDROID update sdk -a -t tools,platform-tools,build-tools-22.0.1,android-10 --no-ui --force --no-https;
+    # SDL2
+    curl -O https://www.libsdl.org/release/SDL2-2.0.3.tar.gz
+    tar -xzvf SDL2-2.0.3.tar.gz
+    mv SDL2-2.0.3 thirdparty/SDL2
   fi
 - sudo pip install pyjavaproperties
 - sudo pip install github3.py