fixes #2405 - disable DNS orchestration during TFTP tests, causing timeouts
refs #2254 - STI Host relationships
fixes #2263 search Hostgroup by label
fixes #2247 Provides an option to disable the use of gravatara

A new setting is added, use_gravatar. It defaults to true. If it is set to false, then the gravatar
call out is not used and only the default user icon is used.
fixes #2367 - Ruby 2.0 support

* require bundler 1.3, preventing ruby-debug19 getting installed on Ruby 2
* update 1.9 gems to install on 2.0 too
* don't use empty arrays in Hash constructor, causes ArgumentError