Implement compression for inline methods.

Implement compression for inline methods.

* net/tramp.el (tramp-inline-compress-start-size): New defcustom.
(tramp-copy-size-limit): Allow also nil.
(tramp-inline-compress-commands): New defconst.
(tramp-find-inline-compress, tramp-get-inline-compress)
(tramp-get-inline-coding): New defuns.
(tramp-get-remote-coding, tramp-get-local-coding): Removed,
replaced by `tramp-get-inline-coding'.
(tramp-handle-file-local-copy, tramp-handle-write-region)
(tramp-method-out-of-band-p): Use `tramp-get-inline-coding'.