Allow extra qualifications when matching json content-type

lib/mock-ajax.js

@@ -117,7 +117,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     var defaults = [
       {
         test: function(xhr) {
-          return xhr.contentType() === 'application/json';
+          return /^application\/json/.test(xhr.contentType());
         },
         parse: function jsonParser(paramString) {
           return JSON.parse(paramString);

spec/javascripts/fake-xml-http-request-spec.js

@@ -145,6 +145,23 @@ describe("FakeXMLHttpRequest", function() {
       expect(xhr.data()).toEqual(data);
     });
 
+    it("should parse json even if there are further qualifiers", function() {
+      var data = {
+        foo: 'bar',
+        baz: ['q', 'u', 'u', 'x'],
+        nested: {
+          object: {
+            with: 'stuff'
+          }
+        }
+      };
+
+      xhr.setRequestHeader('Content-Type', 'application/json; charset=utf-8');
+      xhr.send(JSON.stringify(data));
+
+      expect(xhr.data()).toEqual(data);
+    });
+
     it("should be able to use a custom parser", function() {
       xhr.send('custom_format');
       var custom = {