Fix travis config for master

- use more recent base system, which brings in a more recent gcc version
- install boost (currently 1.54)
- skip explicit installation of packages that were installed already

.travis.yml

@@ -1,11 +1,17 @@
 # Test
-language: c
+sudo: required
+dist: trusty
+language: c++
 compiler:
   - gcc
 #  - clang
 before_install:
+#  - sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
   - sudo apt-get update -qq
+install:
+#  - if [ "$CXX" = "g++" ]; then sudo apt-get install -qq g++-4.9; export CXX="g++-4.9" CC="gcc-4.9"; fi
   - sudo apt-get build-dep -qq gnucash
-  - sudo apt-get install -qq swig xsltproc libdbd-sqlite3
+  - sudo apt-get install -qq swig
+  - sudo apt-get install -qq libboost-all-dev
   - sudo apt-get --reinstall install -qq language-pack-en language-pack-fr
 script: ./autogen.sh && ./configure && make && make check