aos_time.h: added comments to all macros.
All preprocessor directives without arguments (e.g. #endif) are now followed by a comment, indicating where it belongs to (e.g. the preceding #if).
Enhanced the #include tree. 'amiroos.h' is now the central header, which includes all dependencies.
Applied a file structure template to all source files.
Changed all header guards so they will not use unserscores as pre- and postfix.
updated all file headers to 2019
All contents of the os/ folder has been moved one directory up.