This change uses the bwlimit code to apply limits to the receive and
transmit data functions in the HTTP Transport.
This means that all HTTP transactions will have limiting applied -
this includes listings for example.
For HTTP based transorts this makes the limiting in Accounting
redundant and possibly counter productive
This is done by making fs.Config private and attaching it to the
context instead.
The Config should be obtained with fs.GetConfig and fs.AddConfig
should be used to get a new mutable config that can be changed.
- 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.
