Extract cask install to separate step in README

Because the first step is more then 80 character, which is quite long,
so it wraps on GitHub.

README.md

@@ -55,15 +55,16 @@ installed before. You'll need [Cask][cask] to install the dependencies.
 
 I usually use the following workflow when I develop this game:
 
-1. `$ git clone git://github.com/codingteam/pacmacs.el.git && cd pacmacs.el && cask install`;
-2. `$ cask exec emacs`;
-3. `M-x find-file RET /path/to/pacmacs.el/pacmacs.el RET`
-4. `M-x eval-expression RET (add-to-list 'load-path default-directory) RET`;
-5. `M-x eval-buffer RET`;
-6. `M-x pacmacs-start RET`;
-7. `M-x pacmacs-quit RET`;
-8. Change something in the source code;
-9. Go to the step 5.
+1. `$ git clone git://github.com/codingteam/pacmacs.el.git && cd pacmacs.el`;
+2. `$ cask install`
+3. `$ cask exec emacs`;
+4. `M-x find-file RET /path/to/pacmacs.el/pacmacs.el RET`
+5. `M-x eval-expression RET (add-to-list 'load-path default-directory) RET`;
+6. `M-x eval-buffer RET`;
+7. `M-x pacmacs-start RET`;
+8. `M-x pacmacs-quit RET`;
+9. Change something in the source code;
+10. Go to the step 6.
 
 ## Unit Tests ##