Add artist finding tests for new Pixiv URLs.

* Add tests for finding artists using the new Pixiv URLs in Artist#find_all_by_url.
* Add tests for the artist finder JSON API in ArtistsController#finder.
* Add tests for the artist page search form in ArtistsController#index.

test/fixtures/vcr_cassettes/functional/artists_controller/http_/www_pixiv_net/member_illust_php_mode_medium_illust_id_32049358.yml

@@ -0,0 +1,56 @@
+---
+http_interactions:
+- request:
+    method: get
+    uri: http://spapi.pixiv.net/iphone/illust.php?PHPSESSID=696859_80b071246e635ff4098e3f857f1e934a&illust_id=32049358
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Accept:
+      - ! '*/*'
+      User-Agent:
+      - Mechanize/2.7.2 Ruby/1.9.3p327 (http://github.com/sparklemotion/mechanize/)
+      Accept-Encoding:
+      - gzip,deflate,identity
+      Accept-Charset:
+      - ISO-8859-1,utf-8;q=0.7,*;q=0.7
+      Accept-Language:
+      - en-us,en;q=0.5
+      Cookie:
+      - PHPSESSID=696859_80b071246e635ff4098e3f857f1e934a
+      Host:
+      - spapi.pixiv.net
+      Connection:
+      - keep-alive
+      Keep-Alive:
+      - 300
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Server:
+      - nginx
+      Date:
+      - Sun, 05 Oct 2014 18:16:23 GMT
+      Content-Type:
+      - text/html; charset=UTF-8
+      Content-Length:
+      - '0'
+      Connection:
+      - keep-alive
+      X-Host-Time:
+      - '142'
+      Expires:
+      - Thu, 19 Nov 1981 08:52:00 GMT
+      Cache-Control:
+      - no-store, no-cache, must-revalidate, post-check=0, pre-check=0
+      Pragma:
+      - no-cache
+    body:
+      encoding: US-ASCII
+      string: ''
+    http_version: 
+  recorded_at: Sun, 05 Oct 2014 18:16:32 GMT
+recorded_with: VCR 2.9.0

test/fixtures/vcr_cassettes/functional/artists_controller/http_/www_pixiv_net/member_illust_php_mode_medium_illust_id_46170939.yml

@@ -0,0 +1,84 @@
+---
+http_interactions:
+- request:
+    method: get
+    uri: http://spapi.pixiv.net/iphone/illust.php?PHPSESSID=696859_80b071246e635ff4098e3f857f1e934a&illust_id=46170939
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Accept:
+      - ! '*/*'
+      User-Agent:
+      - Mechanize/2.7.2 Ruby/1.9.3p327 (http://github.com/sparklemotion/mechanize/)
+      Accept-Encoding:
+      - gzip,deflate,identity
+      Accept-Charset:
+      - ISO-8859-1,utf-8;q=0.7,*;q=0.7
+      Accept-Language:
+      - en-us,en;q=0.5
+      Cookie:
+      - PHPSESSID=696859_80b071246e635ff4098e3f857f1e934a
+      Host:
+      - spapi.pixiv.net
+      Connection:
+      - keep-alive
+      Keep-Alive:
+      - 300
+  response:
+    status:
+      code: 200
+      message: !binary |-
+        T0s=
+    headers:
+      !binary "U2VydmVy":
+      - !binary |-
+        bmdpbng=
+      !binary "RGF0ZQ==":
+      - !binary |-
+        U3VuLCAwNSBPY3QgMjAxNCAxODoxNjoyMiBHTVQ=
+      !binary "Q29udGVudC1UeXBl":
+      - !binary |-
+        dGV4dC9wbGFpbjsgY2hhcnNldD11dGYtOA==
+      !binary "Q29udGVudC1MZW5ndGg=":
+      - !binary |-
+        NTg3
+      !binary "Q29ubmVjdGlvbg==":
+      - !binary |-
+        a2VlcC1hbGl2ZQ==
+      !binary "WC1Ib3N0LVRpbWU=":
+      - !binary |-
+        MTQ1
+      !binary "RXhwaXJlcw==":
+      - !binary |-
+        VGh1LCAxOSBOb3YgMTk4MSAwODo1MjowMCBHTVQ=
+      !binary "Q2FjaGUtQ29udHJvbA==":
+      - !binary |-
+        bm8tc3RvcmUsIG5vLWNhY2hlLCBtdXN0LXJldmFsaWRhdGUsIHBvc3QtY2hl
+        Y2s9MCwgcHJlLWNoZWNrPTA=
+      !binary "UHJhZ21h":
+      - !binary |-
+        bm8tY2FjaGU=
+      !binary "WC1Db250ZW50LVR5cGUtT3B0aW9ucw==":
+      - !binary |-
+        bm9zbmlmZg==
+    body:
+      encoding: ASCII-8BIT
+      string: !binary |-
+        IjQ2MTcwOTM5IiwiMzI3NzciLCJqcGciLCLjg6bjg4vjgrPjg7zjg7MiLCI0
+        Iiwi44Oe44K144KqIiwiaHR0cDovL2kyLnBpeGl2Lm5ldC9pbWctaW5mL2lt
+        Zy8yMDE0LzA5LzI1LzAwLzU3LzI0LzQ2MTcwOTM5XzEyOHgxMjguanBnIiws
+        LCJodHRwOi8vaTIucGl4aXYubmV0L2ltZzA0L2ltZy9zeW91bmVuX25vX3V0
+        YS9tb2JpbGUvNDYxNzA5MzlfNDgwbXcuanBnIiwsLCIyMDE0LTA5LTI1IDAw
+        OjU3OjI0Iiwi5ryr55S7IOWUhyDjgqrjg6rjgrjjg4rjg6sg44Om44OL44Kz
+        44O844OzIOmOpyIsIlBob3Rvc2hvcCBDb21pY1N0dWRpbyIsIjg5MCIsIjg1
+        NzgiLCIxNzQwMyIsIuWUh+OBjOOBiuawl+OBq+WFpeOCiuOBp+OBmeOAgjxi
+        ciAvPjxiciAvPuaEj+WkluOBq+aPj+OBj+OBruOBq+aZgumWk+OBi+OBi+OC
+        iuOBvuOBl+OBn+OAgjxiciAvPu+8lOaZgumWk+OBu+OBqeOBi+OBi+OBo+OB
+        n+OBqOaAneOBhOOBvuOBmeOAgiIsIjE2IiwsLCI0OTkiLCIxOSIsInN5b3Vu
+        ZW5fbm9fdXRhIiwsIjAiLCwsImh0dHA6Ly9pMi5waXhpdi5uZXQvaW1nMDQv
+        cHJvZmlsZS9zeW91bmVuX25vX3V0YS9tb2JpbGUvNTc4MTUyNV84MC5qcGci
+        LAo=
+    http_version: 
+  recorded_at: Sun, 05 Oct 2014 18:16:31 GMT
+recorded_with: VCR 2.9.0