Component constructor to return this

Crafty component constructors need to return `this`,
otherwise entity creation can't be chained with other
component's constructors after this component's constructor
has been called. Fixed.

Author: weeezes

component/templates/_base.js

@@ -14,6 +14,8 @@ Crafty.c('<%= name %>', {
   // constructor
   <%= name.toLowerCase() %>: function(placeholder) {
     this.placeholder = placeholder;
+
+    return this;
   }
 
 });