travis: Send data to coveralls.io after tests

The PYTHONPATH env variable needed to be removed because it was messing
with pip and cpp-coveralls

Unfortunately adding the '-e build' to coveralls doesn't work to exclude
source files in the build directory, as it won't collect any data then.
If at some point, we have source files that are used by the tests
somewhere inside the build folder that isn't covered by the exclusion
rules, we'll need to add it here

.travis.yml

@@ -9,7 +9,6 @@ env:
     - LIBCXX_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxx-${LLVM_VERSION}.src.tar.xz"
     - LIBCXXABI_URL="http://llvm.org/releases/${LLVM_VERSION}/libcxxabi-${LLVM_VERSION}.src.tar.xz"
     - CMAKE_URL="https://cmake.org/files/v3.6/cmake-3.6.2-Linux-x86_64.tar.gz"
-    - PYTHONPATH="/usr/lib/python2.7/dist-packages:${PYTHONPATH}"
     - JOBS=4
     - POLYBAR_BUILD_TYPE="compile"
 
@@ -25,7 +24,11 @@ matrix:
 
     - compiler: gcc
       env: BUILD_TYPE=Debug POLYBAR_BUILD_TYPE=tests
+      before_install:
+        - pip install --user cpp-coveralls
       script: ${TRAVIS_BUILD_DIR}/common/travis/tests.sh
+      after_success:
+        - coveralls --root .. -E ".*CMakeFiles.*" -e tests -e lib -e build/googletest-src --gcov-options '\-p'
 
     - compiler: gcc
       env: BUILD_TYPE=Release