Document sub-component usage possibility

Author: mpalourdio

README.MD

@@ -65,6 +65,8 @@ You can filter the requests that shouldn't be caught by the interceptor by provi
 
 The different spinners available are referenced in [this class](src/app/spinkits.ts).
 
+Each Spinkit component defined in [SPINKIT_COMPONENTS](src/app/ng-http-loader.module.ts) can be used independently.
+
 ## Requirements
 
 Compatible with Angular 4.3+.