switch travis to dynmodules; use make install to simplify finding backends during tests; show ldd output for debugging linking issues
Make sure geoipbackend pulls in the yaml and geoip libs when loaded dynamically.
Make sure yahttp is linked into remotebackend

Make sure that the yahttp directory is built first
and then link in the resulting library.

Checked with readelf -s .libs/libremotebackend.so | grep NOTYPE
that this fixes the undefined symbol.

Fixes #1732
Mydnsbackend depends on smysql from gymsqlbackend

Fixes #1738