update doc

Author: itchyny

doc/cursorword.txt

@@ -1,10 +1,10 @@
 *cursorword.txt*	Underlines the word under the cursor
 
-Version: 0.2
+Version: 0.3
 Author: itchyny (https://github.com/itchyny)
 License: MIT License
 Repository: https://github.com/itchyny/vim-cursorword
-Last Change: 2015/02/11 12:12:47.
+Last Change: 2016/04/02 15:38:49.
 
 CONTENTS					*cursorword-contents*
 
@@ -49,6 +49,9 @@ is and for what kind of software such configurability is required.
 ==============================================================================
 CHANGELOG					*cursorword-changelog*
 
+0.3	2016-04-02
+	- Compare to empty string instead of using the len function.
+
 0.2	2015-02-10
 	- Call cursorword#highlight on loading the autoload script.