CI: Add libboost-python-dev

Latest travis build failed at cmake stage:

CMake Error at /usr/share/cmake-2.8/Modules/FindBoost.cmake:1202 (message):

  Unable to find the requested Boost libraries.

  Boost version: 1.46.1

  Boost include path: /usr/include

  The following Boost libraries could not be found:

          boost_python

  No Boost libraries were found.  You may need to set BOOST_LIBRARYDIR to the

  directory containing Boost libraries or BOOST_ROOT to the location of

  Boost.

Signed-off-by: Przemo Firszt <przemo@firszt.eu>

.travis.yml

@@ -6,6 +6,7 @@ before_install:
     - sudo apt-get install -y libboost-dev
     - sudo apt-get install -y libboost-filesystem-dev
     - sudo apt-get install -y libboost-program-options-dev
+    - sudo apt-get install -y libboost-python-dev
     - sudo apt-get install -y libboost-regex-dev
     - sudo apt-get install -y libboost-signals-dev
     - sudo apt-get install -y libboost-system-dev