docs(readme): update property converters documentation

Author: jyounce

README.md

@@ -124,6 +124,9 @@ const guid = Guid.create();
 
 
 ### property converters
+All methods convert the attribute's value to a type and returns it.  
+The first param is the attribute's value which is always a string.
+
 * Methods
 	* valueless(val) :boolean
 

src/client/scripts/public/props/converters.js

@@ -1,12 +1,14 @@
-/*******************************************
+/*************************************************************
  * PROPERTY CONVERTERS
- * ----------------------------------------
+ * ----------------------------------------------------------
  * HOW TO USE
- - import Converter from './converters.js';
- *******************************************/
+ - import Converter from './converters.js'; :object
+ * API
+ - All methods convert the attr val to a type and returns it.
+ - The first param is the attr val which is always a string.
+ *************************************************************/
 const Converters = {
 	valueless(val) { // :boolean
-		if (typeof val !== 'string') return val;
 		val = val.trim();
 		if (!val) return true; // valueless attr is empty string
 		return /^true$/i.test(val);