bbbike2.cgi.config for travis-ci
BBBIKE_TEST_SKIP_MAPSERVER for t/mapserver-util.t
add to_app() to psgi file

This fixes the Plack warning:
WARNING: Automatically converting Plack::App::File instance to a PSGI code
reference.  If you see this warning for each request, you probably need
to explicitly call to_app() i.e. Plack::App::File->new(...)->to_app in
your PSGI file.
workaround for If-Modified-Since check
wwwdata.t: mark some tests as TODO for Plack

Actually, the condition is TRAVIS=true, as Starman does not send any
Server HTTP header for identification.
psgi: ConditionalGET for 304 responses