Install also needed boost libraries on travis.

Travis uses Ubuntu 12.04 which ships with Boost 1.46.0. Required
version was lowered therefore.

.travis.yml

@@ -5,7 +5,7 @@ branches:
   only:
     - master
 before_install:
-  - sudo apt-get update; sudo apt-get install qt4-dev-tools libvtk5-dev libvtk5-qt4-dev libnetcdf-dev libshp-dev libgeotiff-dev libboost-dev
+  - sudo apt-get update; sudo apt-get install qt4-dev-tools libvtk5-dev libvtk5-qt4-dev libnetcdf-dev libshp-dev libgeotiff-dev libboost-dev libboost-date-time-dev libboost-filesystem-dev libboost-date-time-dev libboost-filesystem-dev libboost-system-dev
 script: "mkdir build && cd build && cmake -DOGS_BUILD_GUI=ON -DOGS_DONT_USE_OPTIONAL_SUBMODULES=ON .. && cmake .. && make && make test"
 notifications:
   email:

scripts/cmake/ExternalProjectBoost.cmake

@@ -35,7 +35,7 @@ IF(NOT Boost_INCLUDE_DIRS)
 	IF(IS_DIRECTORY /opt/boxen)
 		SET(BOOST_ROOT /opt/boxen/homebrew)
 	ENDIF()
-	FIND_PACKAGE(Boost 1.48.0 COMPONENTS ${BOOST_LIBS_TO_BUILD})
+	FIND_PACKAGE(Boost 1.46.0 COMPONENTS ${BOOST_LIBS_TO_BUILD})
 	IF(Boost_FOUND)
 		INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
 		RETURN()