Support wildcard for target in /query

[doublemarket]

You can use * as a wildcard for the target value in the /query endpoint.

Request:

{
  "panelId": 1,
  "range": {
    "from": "2016-10-31T06:33:44.866Z",
    "to": "2016-10-31T12:33:44.866Z",
    "raw": {
      "from": "now-6h",
      "to": "now"
    }
  },
  "rangeRaw": {
    "from": "now-6h",
    "to": "now"
  },
  "interval": "30s",
  "intervalMs": 30000,
  "targets": [
     { "target": "a:b:c:upper_*:value", refId: "A" }
  ],
  "format": "json",
  "maxDataPoints": 550
}

Response:

[
  {
    "target":"a:b:c:upper_75:value",
    "datapoints":[
      [622,1450754160000],
      [365,1450754220000]
    ]
  },
  {
    "target":"a:b:c:upper_90:value",
    "datapoints":[
      [861,1450754160000],
      [767,1450754220000]
    ]
  }
]

[coveralls]

Coverage increased (+1.1%) to 75.556% when pulling 0c6d521 on query-wildcard into 8e8be72 on master.