update README for usage and installation

Author: zbryikt

README.md

@@ -3,6 +3,28 @@
 Stateful CSS animation.
 
 
+## Installation
+
+download and include [state.css](https://raw.githubusercontent.com/loadingio/state.css/v0.0.1/dist/state.min.css):
+
+```
+    <link rel="stylesheet" type="text/css" href="state.min.css"/>
+```
+
+you an use a CDN, such as, from jsDelivr:
+
+```
+    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/gh/loadingio/state.css@v0.0.1/dist/state.min.css"/>
+```
+
+
+## Usage
+
+Add CSS class of desired state to your DOM element, along with additional `ld` class.  Currently we only implement one animation ( ld-flip-ltr ):
+
+    <div class="ld ld-flip-ltr"> ... ( your content ) ... </div>
+
+
 ## LICENSE
 
 MIT License