add ExpandableTextView（可展开和收缩内容的TextView）

可已展开收缩内容的TextView。  
项目地址：https://github.com/Manabu-GT/ExpandableTextView

Author: zhengxiaopeng

README.md

@@ -713,6 +713,12 @@ EditText 的 Material Design 实现。包含 [Google Material Design Spec](http:
 效果图：<img height="500px" src="https://camo.githubusercontent.com/1223e37d084e84ec0e22a1b27e7513661d0e1b39/687474703a2f2f692e696d6775722e636f6d2f773934576f53582e706e67" />   
 <a href="https://github.com/Trinea/android-open-project#%E7%9B%AE%E5%89%8D%E5%8C%85%E6%8B%AC" title="返回目录" style="width:100%"><img src="http://farm4.staticflickr.com/3737/12167413134_edcff68e22_o.png" align="right"/></a>  
 
+1. ExpandableTextView  
+可展开和收缩内容的TextView。  
+项目地址：https://github.com/Manabu-GT/ExpandableTextView   
+效果图：<img height="500px" src="https://camo.githubusercontent.com/8bf46083b3bd152c2051ae4c234649dbbb975376/68747470733a2f2f7261772e6769746875622e636f6d2f4d616e6162752d47542f457870616e6461626c6554657874566965772f6d61737465722f6172742f726561646d655f64656d6f2e676966" />   
+<a href="https://github.com/Trinea/android-open-project#%E7%9B%AE%E5%89%8D%E5%8C%85%E6%8B%AC" title="返回目录" style="width:100%"><img src="http://farm4.staticflickr.com/3737/12167413134_edcff68e22_o.png" align="right"/></a>   
+
 #### 九、ScrollView  
 1. Discrollview  
 支持滚动时Item淡入淡出，平移，缩放效果的ScrollView