Added statistics functionality (APIv2 only)

https://www.hipchat.com/docs/apiv2/method/get_room_statistics
added Room#update_room method, specs, and docs

https://www.hipchat.com/docs/apiv2/method/update_room
Allow multiple rooms to be notified with the same message
Suggest using room name or id for more robust configuration
Room config is an array now
Adds more flexibility to chef msg options

Without breaking existing options or cluttering the init method with
options, this adds the ability to specify an arbitrary number of
notification options, such as message_format.
Adds message prefix to chef handler

Adds an option to prefix a string before the message, such as for an
@all mention.
Merge pull request #103 from seafoox/feature-apiv2-statistics

Added statistics functionality (APIv2 only)
Merged Perceptive-Cloud-update_room, resolved conflict
Merge branch 'Perceptive-Cloud-update_room'
ignore intellij
Merge pull request #110 from joraff/chef-mods

Chef mods
Merge pull request #106 from sonyakc/master

Allow multiple rooms to be notified with the same message