removed the non-working gridserv + google2brb experiment

It was probably never working properly, and there's now
the mapnik maps (better then the mapserver-generated maps) and
the tile server at bbbike.org.
javascript files: fixed all redeclaration warnings
JSTest: removed diagnostics about redeclaration warning

The diagnostics was wrong: redeclared js variables within the same
function are worth a warning, because javascript does not have block
scope, just function scope.
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"
more system prereqs needed for Geo::Proj4 and DB_File under Ubuntu
travis.yml: added agrep to list of pre-installed packages
travis: install all problematic perl modules now in .travis.yml

Instead of removing problematic perl modules from PREREQ_PM, it's
better (especially faster) to install it via apt-get.