[coding] remove stdin/stdout fd variabled - replace with constants
[fs] wrong debug print in sim block api
[fs] add file_write API - without fs backends
[fs] file_write for builtin fs - easy - it's read only...
[fs] file_write for localfs
[fs] file_write for FAT fs
[fs] bugfix - fix memory leak in file read API
[fs] add writeFileSync() API
[fs] added file test - very initial