Travis CI + Yacc replacement

Travis:
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I've spend some time on getting the whois server to build properly through the Travis CI system. The advantage of this file is that people who fork and modify the Whois Server can easily see if their modifications contain errors or not! This .travis.yml file is my christmas present to RIPE NCC this year ;-) An example of a build log is available here: https://travis-ci.org/job/whois/builds/15534257

Yacc:
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I've located the sources of the yacc.linux and yacc.macosx binairies that were included in this git repository. The inclusion of these 32-bit binaries seemed to prevent building through Travis CI, therefore I changed the build scripts to compile yacc from the byaccj-p2 sources in the tools directory if the byaccj binary does not exist yet. I've included the sources instead of making a submodule or having the make scripts git clone something because I'd prefer that the whois server can be build on offline systems. I also do not expect a lot of patches back to the 1999 upstream. This pull request addresses https://github.com/RIPE-NCC/whois/issues/104