Add more Qt dependencies (network...) for the various components.
Hack to help the compilers on Travis find the Qt5 headers.

The clean version of this patch would be to properly have the header
paths set by CMake. On a Ubuntu 14.04, this patch is not needed, but
Travis uses a 12.04.
Add the -fPIE compiler flag.
Set the default build type to debug.
Force the use of C++11 mode.
Typo ; fix the server not being correctly linked to the common lib.
Add some tests dependencies to the linker.
Update compilers version on Travis, and dump version info.

From http://stackoverflow.com/questions/22111549/travis-ci-with-
clang-3-4-and-c11.
Make sure the Qt version used is >= 5.2.

Not sure if Qt5.3 will be compatible with this, but as I can not find a
pre-packaged Qt5.3 version this is not an issue for the moment.
Remove explicit include path (no longer needed).
Dump versions in the before_script session.
Use Qt5.2 on Travis.
Travis: put the CMake build into the "install" section.
Merge pull request #4 from Neki/topic/bf_fix_travis_builds

Use Qt5.2 on Travis, more recent compilers, and clean the install script.