Merged in sstok/bitbucket-api/fix-PullRequests (pull request gentlero#6)

Fixed Content-Type for `PullRequests::accept` and `PullRequests::decline`.

Author: vimishor

lib/Bitbucket/API/Repositories/PullRequests.php

@@ -290,7 +290,8 @@ public function accept($account, $repo, $id, $params = array())
     {
         return $this->getClient()->setApiVersion('2.0')->post(
             sprintf('repositories/%s/%s/pullrequests/%d/merge', $account, $repo, $id),
-            $params
+            json_encode($params),
+            array('Content-Type' => 'application/json')
         );
     }
 
@@ -308,7 +309,8 @@ public function decline($account, $repo, $id, $params = array())
     {
         return $this->getClient()->setApiVersion('2.0')->post(
             sprintf('repositories/%s/%s/pullrequests/%d/decline', $account, $repo, $id),
-            $params
+            json_encode($params),
+            array('Content-Type' => 'application/json')
         );
     }
 }