Added Data change observable

README.md

@@ -172,7 +172,7 @@ adapter.setOnDataUpdateListener {
 
 Use tools attribute for previewing Layout, so you don't need to always run application
 
- - **recyclerview**
+**recyclerview**
 
   ``` xml
  tools:listitem="@layout/inflater_category"
@@ -182,23 +182,23 @@ Use tools attribute for previewing Layout, so you don't need to always run appli
 
 ```
 
- - **layout**
+**layout**
 
  ``` xml
  tools:text="Sample Text"
  tools:visibility="VISIBLE"
  tools:background="@color/colorPrimary"
 ```
 
- - **android predefine sample data**
+**android predefine sample data**
 
 ``` xml
  tools:text="@tools:sample/cities,first_names,us_phones,lorem,lorem/random"
  tools:background="@tools:sample/backgrounds/scenic"
  tools:src="@tools/avatars"
 ```
 
- - **custom sample data**
+**custom sample data**
 
     To create your fake/sample data folder,
     just right click on the “app” folder then “new > Sample Data directory” <br />