add: NNMacrosCheck.h

fix: c++ 编译错误

modify: 删除 NNMacros.podspec 中 s.static_framework = true

add: The following code is copied from https://raw.githubusercontent.com/ReactiveCocoa/ReactiveObjC/master/ReactiveObjC/extobjc/EXTScope.h
and deleted and modified as needed.

fix: 头文件输出
update: README.md
change: NNMacrosLazyGetterDemo/NNMacrosSynthesizeDemo
change: 重新实现 nn_associated_setter/nn_associated_getter

fix: xcode11 上 nn_lazygetter 格式化问题

fix: nn_associated_setter 中存储 key 获取失败问题

update: README.md
delete: 删除注释代码
delete: setter 方法输入提示
change: 修改 synthesize getter setter 实现

fix: framework 工程 NNMacrosSandbox.h 找不到问题
fix: demo 丢失的 scheme
fix: nn_categorysetter_store_key 中存储 key 获取失败问题

add: NNMacrosSynthesizeDemo
add: weak 属性 bug
change: NSObject+NNMacrosAssociatedSynthesize.m 变量命名规范
add: NN_arg2CString 宏
change: NN_Color 命名规范调整
change: lazygetter 接口重命名 nn_lazygetter
change: 重构 synthesize 实现 synthesize getter setter 接口重命名