Update Yahoo lookup to reflect API changes.

"Results" key is now "Result" and is not an array when only one result.
Update code and response fixtures to reflect this.

lib/geocoder/lookups/yahoo.rb

@@ -12,8 +12,15 @@ module Geocoder::Lookup
 
     def results(query)
       return [] unless doc = fetch_data(query)
-      if doc = doc['ResultSet'] and doc['Error'] == 0
-        return doc['Found'] > 0 ? Array(doc['Result']) : []
+      doc = doc['ResultSet']
+      # seems to have Error == 7 when no results, though this is not documented
+      if [0, 7].include?(doc['Error'].to_i)
+        if doc['Found'].to_i > 0
+          r = doc['Result']
+          return r.is_a?(Array) ? r : [r]
+        else
+          return []
+        end
       else
         warn "Yahoo Geocoding API error: #{doc['Error']} (#{doc['ErrorMessage']})."
         return []

test/fixtures/yahoo_garbage.json

-{
-  "ResultSet":{
-    "version":"1.0",
-    "Error":0,
-    "ErrorMessage":"No error",
-    "Locale":"us_US",
-    "Quality":87,
-    "Found":1,
-    "Result":[{
-      "quality":9,
-      "latitude":"55.008390",
-      "longitude":"-5.822485",
-      "offsetlat":"54.314072",
-      "offsetlon":"-2.230010",
-      "radius":1145100,
-      "boundingbox":{
-        "north":"60.854691",
-        "south":"49.162090",
-        "east":"1.768960",
-        "west":"-13.413930"
-      },
-      "name":"",
-      "line1":"",
-      "line2":"",
-      "line3":"",
-      "line4":"United Kingdom",
-      "cross":"",
-      "house":"",
-      "street":"",
-      "xstreet":"",
-      "unittype":"",
-      "unit":"",
-      "postal":"",
-      "neighborhood":"",
-      "city":"",
-      "county":"",
-      "state":"",
-      "country":"United Kingdom",
-      "countrycode":"GB",
-      "statecode":"",
-      "countycode":"",
-      "timezone":"Europe/London",
-      "areacode":"",
-      "uzip":"",
-      "hash":"",
-      "woeid":23424975,
-      "woetype":12
-    }]
-  }
-}

test/fixtures/yahoo_madison_square_garden.json

 {
+  "@lang": "en-US",
   "ResultSet": {
-    "version":"1.0",
-    "Error":0,
+    "@version": "2.0",
+    "@lang": "en-US",
+    "Error": "0",
     "ErrorMessage": "No error",
-    "Locale":"us_US",
-    "Quality":90,
-    "Found":1,
-    "Result":[{
-      "quality":90,
+    "Locale": "en-US",
+    "Found": "1",
+    "Quality": "90",
+    "Result": {
+      "quality": "90",
       "latitude": "40.750381",
       "longitude": "-73.993988",
       "offsetlat": "40.750381",
       "offsetlon": "-73.993988",
-      "radius":100,
+      "radius": "100",
+      "boundingbox": {
+        "north": "40.750832",
+        "south": "40.749931",
+        "east": "-73.993393",
+        "west": "-73.994591"
+      },
       "name": "Madison Square Garden",
       "line1": "Madison Square Garden",
       "line2": "New York, NY 10001",
       "line3": "",
       "line4": "United States",
+      "cross": "",
       "house": "",
       "street": "",
       "xstreet": "",
       "unittype": "",
       "unit": "",
       "postal": "10001",
-      "neighborhood":"",
+      "neighborhood": "Garment District|Midtown|Midtown West|Manhattan",
       "city": "New York",
       "county": "New York County",
       "state": "New York",
@@ -32,15 +41,12 @@
       "countrycode": "US",
       "statecode": "NY",
       "countycode": "",
-      "uzip":"10001",
-      "hash":"",
-      "woeid":23617041,
-      "woetype":20,
-      "cross":"",
       "timezone": "America/New_York",
-      "neighborhood":"Garment District|Midtown|Midtown West|Manhattan",
       "areacode": "212",
-      "boundingbox":{"north":"40.750832","south":"40.749931","east":"-73.993393","west":"-73.994591"}
-    }]
+      "uzip": "10001",
+      "hash": "",
+      "woeid": "23617041",
+      "woetype": "20"
+    }
   }
 }

test/fixtures/yahoo_no_results.json

 {
+    "@lang": "en-US",
     "ResultSet": {
-    "version":"1.0",
-    "Error":0,
-    "ErrorMessage":"No error",
-    "Locale":"us_US",
-    "Quality":10,
-    "Found":0
+        "@version": "2.0",
+        "@lang": "en-US",
+        "Error": "7",
+        "ErrorMessage": "No result",
+        "Locale": "en-US",
+        "Found": "0",
+        "Quality": "0"
     }
 }