It's migrated from e4crypt.
Adds an example to the f2fscrypt manpages.
v3, add /tools/f2fscrypt to .gitignore
v2, migrate those micro defines for encrypt to f2fs internal,
drop unless of libsha etc.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
