If the destination of os.rename() exists then it will be overwritten if it
is a file.  This is the POSIX behaviour, which is also the CPython
behaviour, and so we follow suit.

See issue #2598 for discussion.

This is an object-oriented approach, where uos is only a proxy for the
methods on the vfs object.  Some internals had to be exposed (the STATIC
keyword removed) for this to work.

Fixes #2338.

Shares the code with remove() method due to the same underlying f_unlink()
FatFs operation.

The time stamp is taken from the RTC for all newly generated
or changed files. RTC must be maintained separately.
The dummy time stamp of Jan 1, 2000 is set in vfs.stat() for the
root directory, avoiding invalid time values.

The call to stat() returns a 10 element tuple consistent to the os.stat()
call. At the moment, the only relevant information returned are file
type and file size.

Copy-paste issue, with the original mistake in stmhal.

Ported from stmhal.

Ported from stmhal.

These changes are in line with similar changes in other modules, and
with standard Python interface.

Based on stmhal implementation - rather small, so just duplicating.

This implements OO interface based on existing fsusermount code and with
minimal changes to it, to serve as a proof of concept of OO interface.

Examle of usage:

bdev = RAMFS(48)
uos.VfsFat.mkfs(bdev)
vfs = uos.VfsFat(bdev, "/ramdisk")
f = vfs.open("foo", "w")
f.write("hello!")
f.close()