README.rst: Change README.md's image

This is to replace the image at coala-html
repository in README.md file with that
of coala-bears.

coala#151

README.rst

@@ -1,6 +1,26 @@
 README
 ======
-.. image:: https://cloud.githubusercontent.com/assets/7521600/15992701/ef245fd4-30ef-11e6-992d-275c5ca7c3a0.jpg
+
+.. Start ignoring LineLengthBear
+
+::
+
+                                                         .o88Oo._
+                                                        d8P         .ooOO8bo._
+                                                        88                  '*Y8bo.
+                                          __            YA                      '*Y8b   __
+                                        ,dPYb,           YA                        68o68**8Oo.
+                                        IP'`Yb            "8D                       *"'    "Y8o
+                                        I8  8I             Y8     'YB                       .8D
+                                        I8  8P             '8               d8'             8D
+                                        I8  8'              8       d8888b          d      AY
+         ,gggo,    ,ggggo,    ,gggo,gg  I8 dP    ,gggo,gg   Y,     d888888         d'  _.oP"
+        dP"  "Yb  dP"  "Y8go*8P"  "Y8I  I8dP    dP"  "Y8I    q.    Y8888P'        d8
+       i8'       i8'    ,8P i8'    ,8I  I8P    i8'    ,8I     "q.  `Y88P'       d8"
+      ,d8,_    _,d8,   ,d8' d8,   ,d8b,,d8b,_ ,d8,   ,d8b,       Y           ,o8P
+    ooP""Y8888PP*"Y8888P"   "Y8888P"`Y88P'"Y88P"Y8888P"`Y8            oooo888P"
+
+.. Stop ignoring LineLengthBear
 
 ABOUT
 =====