KaiOS系统框架
最早自下而上分成Gonk-Gecko-Gaia层，代码有同名的目录，现在已经不用这种称呼。
按照官网3.0的版本迭代介绍，2.5->3.0已经将系统更新成如下部分：
仅分为上层web应用和底层平台核心，通过WebAPIs连接上下层，这也是kaios系统升级变更较大的部分。
KaiOS Product is decoupled into two components : Core and App Profile.
App Profile：
A collection of built-in web apps, which represents the user interfacing functions of KaiOS for a given device form factor.
Core：
The underlying platform that consists of the Web application runtime, i.e. Gecko, plus the hardware adaptation layer and a few other supporting module.
