Path-preserving policy would need to look for the parent dir of operating path. Therefor if the operating path is the
same path as root passed in during NewFs, there would be no room for uplooking. And also About() might have
problem if the folder is no exist. RootFs is added to solve this problem.
- Change rclone/fs interfaces to accept context.Context
- Update interface implementations to use context.Context
- Change top level usage to propagate context to lover level functions
Context propagation is needed for stopping transfers and passing other
request-scoped values.
Before this change the union remote was using whether the writable
union could poll for changes to decide whether the union mount could
poll for changes.
The fix causes the union backend to signal it can poll for changes if
**any** of the remotes can poll for changes.
Implement optional interfaces
- Purge
- PutStream
- Copy
- Move
- DirMove
- DirCacheFlush
- ChangeNotify
- About
Make Hashes() return the intersection of all the hashes supported by the remotes
* Fix error handling in List and NewObject
* Fix Precision in case we have precision > time.Second
* Fix Features - all binary features are possible
* Fix integration tests using new test facilities
