vendor: update all dependencies to latest versions

vendor/github.com/russross/blackfriday/README.md

@@ -1,4 +1,4 @@
-Blackfriday [![Build Status](https://travis-ci.org/russross/blackfriday.svg?branch=master)](https://travis-ci.org/russross/blackfriday)
+Blackfriday [![Build Status](https://travis-ci.org/russross/blackfriday.svg?branch=master)](https://travis-ci.org/russross/blackfriday) [![GoDoc](https://godoc.org/github.com/russross/blackfriday?status.svg)](https://godoc.org/github.com/russross/blackfriday)
 ===========
 
 Blackfriday is a [Markdown][1] processor implemented in [Go][2]. It
@@ -93,6 +93,22 @@ installed in `$GOPATH/bin`.  This is a statically-linked binary that
 can be copied to wherever you need it without worrying about
 dependencies and library versions.
 
+### Sanitized anchor names
+
+Blackfriday includes an algorithm for creating sanitized anchor names
+corresponding to a given input text. This algorithm is used to create
+anchors for headings when `EXTENSION_AUTO_HEADER_IDS` is enabled. The
+algorithm has a specification, so that other packages can create
+compatible anchor names and links to those anchors.
+
+The specification is located at https://godoc.org/github.com/russross/blackfriday#hdr-Sanitized_Anchor_Names.
+
+[`SanitizedAnchorName`](https://godoc.org/github.com/russross/blackfriday#SanitizedAnchorName) exposes this functionality, and can be used to
+create compatible links to the anchor names generated by blackfriday.
+This algorithm is also implemented in a small standalone package at
+[`github.com/shurcooL/sanitized_anchor_name`](https://godoc.org/github.com/shurcooL/sanitized_anchor_name). It can be useful for clients
+that want a small package and don't need full functionality of blackfriday.
+
 
 Features
 --------
@@ -114,7 +130,7 @@ All features of Sundown are supported, including:
     know and send me the input that does it.
 
     NOTE: "safety" in this context means *runtime safety only*. In order to
-    protect yourself agains JavaScript injection in untrusted content, see
+    protect yourself against JavaScript injection in untrusted content, see
     [this example](https://github.com/russross/blackfriday#sanitize-untrusted-content).
 
 *   **Fast processing**. It is fast enough to render on-demand in
@@ -169,6 +185,15 @@ implements the following extensions:
     You can use 3 or more backticks to mark the beginning of the
     block, and the same number to mark the end of the block.
 
+    To preserve classes of fenced code blocks while using the bluemonday
+    HTML sanitizer, use the following policy:
+
+    ``` go
+    p := bluemonday.UGCPolicy()
+    p.AllowAttrs("class").Matching(regexp.MustCompile("^language-[a-zA-Z0-9]+$")).OnElements("code")
+    html := p.SanitizeBytes(unsafe)
+    ```
+
 *   **Definition lists**. A simple definition list is made of a single-line
     term followed by a colon and the definition for that term.
 
@@ -242,6 +267,8 @@ are a few of note:
     point. In particular, it does not do any inline escaping, so input
     that happens to look like LaTeX code will be passed through without
     modification.
+    
+*   [Md2Vim](https://github.com/FooSoft/md2vim): transforms markdown files into vimdoc format.
 
 
 Todo