updated msi/deb version to 2.1.1
updated source version to 2.0.9
updated build-msi.py
[scripts] updated build-server.py
[scripts] added upgrade scripts for winserver
updated linux client icons
[scripts] improved upgrade shell scripts

1) update the "seafile-server-latest" symlink when upgrading
2) Improved the scripts with the online static checker http://www.shellcheck.net/
update version to 2.1.0
Handle invalid UTF-8 characters in commit objects.
[server] Add change repo password RPC.
[server] Add 0644 to file mode when upload/update from web.
Improve description for merge commits.

If a commit object satisfies:
commit->second_parent_id != NULL && commit->new_merge && !commit->conflict.
Then this commit is an auto-merge commit with no useful description.
Seahub should not display this commit to the user.
Add new fields to RPC commit object.
[server] Include file revisions before rename.
Fix utf8 filename case conflicts
Undo previous commit.
[http] Set Content-Type for common file types.
[client] Don't popup "auto merge" notifications.
update version to 2.1.0
[script] migrate customization in server update script