[client] Improve case conflict handling.

[mac] update to v1.6.1-mac

[server] add mysql upgrade sql

[client] Fix a few bugs.

* Remove unmerged index entries on commit.
* Ignore update_worktree() errors in clone and merge.

[client] Fix a few bugs.

* Remove unmerged index entries on commit.
* Ignore update_worktree() errors in clone and merge.

update version to 1.6.0

[client] Add some temporary debug messages.

[cli] use urllib2 instead of curl

[cli] use urllib2 instead of curl

[mac] Update to version 1.5.3