Fix address_len() for HOSTNAME addresses

Didn't include the null byte string terminator in the Address struct
size. Fixes #80.
tests: connect rather than sleep to test readiness

This should fix a recurring issue with Valgrind test in Travis-CI runs,
the one second sleep is not always enough time for the proxy to fully
start when preforming tests.
Asynchronous DNS resolver using udns.
Optionally link against libudns for DNS resolution
Merge branch 'master' into udns
Nonblocking DNS resolution
Updating Debian, Redhat and Travis-CI files for 0.3 release