Add tween engine lib to travis script to fix the build

.travis.yml

@@ -2,6 +2,8 @@ language: cpp
 compiler:
  - gcc
 before_install:
+ - git clone https://github.com/cpp3ds/universal-tween-engine-cpp.git tween
+ - "cd tween && make ; cd -"
  - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
  - sudo apt-get -qq update
  - sudo apt-get -qq install libgtest-dev g++-4.8

test/run.sh

@@ -1,5 +1,5 @@
 echo "Compiling unit tests..."
-g++ main.cpp -o test -L../lib -I../include -std=c++11 -lgtest -lpthread -lcpp3ds -DTESTING
+g++ main.cpp -o test -L../lib -I../include -L../tween/lib -I../tween/include -std=c++11 -lgtest -lpthread -lcpp3ds -ltween -DTESTING
 echo "Running unit tests..."
 ./test -v
 result=$?