Merge pull request #81 from WeweTom/master

Auto merge by kpm server
更新文档
Merge pull request #82 from WeweTom/master

Auto merge by kpm server
update changelog
update 1.2 demo
线条样式
1. legend 添加destroy方法
2. realtime 添加legend
Merge branch 'master' into 1.3
Merge branch 'master' of https://github.com/kissygalleryteam/kcharts into 1.3