Merge pull request #49 from ktmud/master

使用 `wechat` 模块，弃用太死板的 `wechat-mp`
添加简单测试和覆盖率
Merge pull request #50 from JacksonTian/coverage

添加简单测试和覆盖率
minor update on docs; keep the original webot.watch accesible
Merge pull request #52 from ktmud/compatibility

minor update on docs; keep the original webot.watch accesible
增加参数处理和返回object的 test case
add more file in npmignore;
update history