collectors/haproxy - more data gathering

collectors/haproxy/lib/panoptimon-collector-haproxy/haproxy.rb - tweak info capture
collectors/haproxy/spec/haproxy_spec.rb                        - tested
collectors/haproxy - tie a knot in it here

collectors/haproxy/README.md                                   - output spec
collectors/haproxy/lib/panoptimon-collector-haproxy/haproxy.rb - output impl