[WIP] Install `hipchat` gem library.

- [ ] Install `hipchat` gem library
- [ ] Update `sensu-plugin` gem library
Install `hipchat` gem library and update prerequisite gems.
Merge pull request #133 from kazu634/sensu-install-hipchat-gem

Install `hipchat` gem library.
Install the latest `knife-solo` gem library to support `environment`.
Introduce `development` environment.
[sensu-custom] Support `environment`
[fluentd-custom] Support `environment`
[growthforecast] Support `environment`
[jenkins] Support `environment`
[kazu634] Support `environment`
[webapp] Support `environment`
[wordpress] Support `environment`