Added HipChat service for alerting.

[ericiles]

Implements #119

This code has been tested and has successfully sent alerts to HipChat as of 12/28/2015.

Usage:

stream
    .from().measurement('cpu')
    .where(lambda: "host" == 'serverA')
    .groupBy('host')
    .window()
        .period(10s)
        .every(10s)
    .mapReduce(influxql.count('idle'))
    .alert()
        .id('kapacitor/{{ .Name }}/{{ index .Tags "host" }}')
        .info(lambda: "count" > 6.0)
        .warn(lambda: "count" > 7.0)
        .crit(lambda: "count" > 8.0)
        .hipChat()
            .room('1234567')
            .token('testtoken1234567')

Configuration:

[hipchat]
  # Configure HipChat.
  enabled = false
  # The HipChat API URL. Replace subdomain with your
  # HipChat subdomain.
  url = "https://subdomain.hipchat.com/v2/room"
  # Visit https://www.hipchat.com/docs/apiv2
  # for information on obtaining your room id and
  # authentication token.
  # Default room for messages
  room = ""
  # Default authentication token
  token = ""
  # If true then all alerts will be sent to HipChat
  # without explicitly marking them in the TICKscript.
  global = false

• CHANGELOG.md updated
• Rebased/mergable
• Tests pass
• Sign CLA (if not already signed)

[nathanielc]

Should we URL escape the room and token vars so the config doesn't have to do things like Test%20Room? See the answer to this SO question. It has a good example of how to safely craft the URL. http://stackoverflow.com/questions/13820280/encode-decode-urls

[ericiles]

In a test I did, it appears that the http.Post automatically url encodes the url string. However, I didn't see this behavior documented, so to play it safe, I went ahead and implented the net/url method of parsing the URL in order to encode it, so that if the http.Post behavior changes in the future, it doesn't break this.

[nathanielc]

Great looks good.

[nathanielc]

@ericiles This is great work! Just a few small changes to make the URL creation safer and easier for the config and this should be good to go.

How do you like the changes to having lists of handlers? Did that help clean it up a bit for you?

[ericiles]

Having lists of handlers made things much nicer. Definitely an improvement. I have made the requested changes.