Upgrade SDL version for Travis builds

Author: swatteau

Diff for: .travis.yml

@@ -11,9 +11,9 @@ env:
     - LD_LIBRARY_PATH: /usr/local/lib
 install:
   - cd ..
-  - time wget -q http://www.libsdl.org/release/SDL2-2.0.5.tar.gz
-  - time wget -q http://www.libsdl.org/projects/SDL_image/release/SDL2_image-2.0.1.tar.gz
-  - time wget -q http://www.libsdl.org/projects/SDL_ttf/release/SDL2_ttf-2.0.14.tar.gz
+  - time wget -q http://www.libsdl.org/release/SDL2-2.0.10.tar.gz
+  - time wget -q http://www.libsdl.org/projects/SDL_image/release/SDL2_image-2.0.5.tar.gz
+  - time wget -q http://www.libsdl.org/projects/SDL_ttf/release/SDL2_ttf-2.0.15.tar.gz
   - time tar xf SDL2-*.tar.gz
   - time tar xf SDL2_image-*.tar.gz
   - time tar xf SDL2_ttf-*.tar.gz