Add a detailed description for AAChartKit

AAChartKit/AAChartKit/AAChartKit.podspec

@@ -1,7 +1,18 @@
 Pod::Spec.new do |s|
     s.name         = 'AAChartKit'
     s.version      = '2.0.7'
-    s.summary      = 'An elegant and friendly chart library for iOS developer'
+    s.summary      = '
+An elegant and friendly chart library for iOS developer
+***
+## Features:
+1. Support `iOS 6`、`ARC` & `Objective C`.
+2. Powerful,support the  `column chart` `bar chart` `line chart` `spline chart` `pie chart` `polar chart` `radar chart` and other graphics.
+3. Interactive、animated,the `animation` is exquisite and deligate.
+4. Support `chain programming syntax` like *Masonry* 
+5. `AAChartView + AAChartModel = Chart`  In the AAChartKit,it follows a minimalist formula: ` Chart view + Chart model = The chart you want`.  
+***
+
+'
     s.homepage     = 'https://github.com/AAChartModel/AAChartKit'
     s.license      = 'MIT'
     s.authors      = {'An An' => '[email protected]'}