Merge pull request #1421 from jmtoball/master

Annoate Blame's file() function as asynchronous.

lib/blame.js

@@ -7,6 +7,7 @@ var _file = Blame.file;
 /**
  * Retrieve the blame of a file
  *
+ * @async
  * @param {Repository} repo that contains the file
  * @param {String} path to the file to get the blame of
  * @param {BlameOptions} [options] Options for the blame