basic.t: BBBikeApacheSessionCountedHandler skipped if mod_perl2 not available

Note that the skip check is only active if BBBIKE_TEST_NO_CGI_TESTS
was set.
first steps for travis testing

* don't prereq "difficult" modules like Image::Magick or X11::Protocol
* use "test-no-cgi" target
added .travis.yml
added Geo::Proj4 to list of uninstallable dependencies
travis build: removed 5.8 because of DBD::XBase issues
travis: added GD and dependencies to the list of uninstallable dependencies
added DB_File as a prereq

Usually installed with Perl itself, but may be missing, e.g.
with self-compiled Perls (perlbrew! travis!).
travis: install deps via apt-get, call "make ext"