~xdavidwu/saf-sftp

don't reuse SFTPv3Client, it's not costy and this enables concurrency
ReadTask: always try to close the file
add mount path settings
show configured values on create
adjust inputType
close connection on query roots
notify root change when config changes
NetworkOnMainThreadException workaround
reuse connection whenever possible
add license for this project
add README
include license for sshlib
init commit