[client] edit server address of a repo

If the ccnet-server address is changed (either address or
port is changed), on the client side the user should edit the
repo's server address/port accorodingly.
[scripts] add seaf-cli.py script

It can do the following works in command line:
 * start seafile
 * clone a repo
 * sync a repo
 * remove a repo
Rewrite seaf-cli
[cli] Add command 'list' and test commands 'sync' and 'desync'
[cli] Add 'status' command
[cli] Move seaf-cli to app/seaf-cli
[cli] improve and install seaf-cli
[cli] Add stop command
[cli] Add support for encrypted repos
[seaf-cli] improve seaf-cli
Merge branch 'seaf-cli'
[client] add manpage for seaf-cli
Merge branch 'server-addr'
improve debian/