[common] cleanup avl and related code
[common] remove unused functions

 - seaf_repo_manager_get_repo_prefix
 - seaf_repo_manager_repo_exists_prefix
[client] land new changes of new-sync for osx
[build] fix bus error while execute make -jN (N>1)
[win] Fix a memory bug when unsyncing a library.
[win] Fix command handling bug in wt-monitor.
Update msi version to 3.1.1.
[win] Fix command handling bug in wt-monitor.
Merge branch 'new-sync-osx' into 3.1
Check openssl in configure.ac and enable fuse option for mac
[client] make the compiler happy when compiling with -Wall flag
[client] Fix rename problem on Windows and Mac.

The case is that a file/dir's name changes in cases.
Merge branch 'cleanup_avl' into 3.1
Clean up repo hash table code.
Remove some code with copyright problems.
Remove bitfield code.
[scripts] add seaf-gc wrapper
Merge pull request #756 from Chilledheart/scripts_add_gc

[scripts] add seaf-gc wrapper
[server] List corrupted repos for admin and owner.
[server] Don't return corrupted repos for owner.