- Made flist_find() and receive_file_entry() static functions.

- Made flist_find() and receive_file_entry() static functions.
- Changed receive_file_entry() args.
- We now store the directory depth into file->dir.depth when
  receiving the file list.  This will be used to aid in the
  traversal of the file list on the receiving side for things
  such as the future --fuzzy option and better --delete-during
  processing.
- Fixed a bug when -R was used with "." as a source directory:
  subdirectories were not being promoted to FLAG_DEL_START when
  --delete-during was specified.
- Refer to the old basedir variable as dir.root.
- Got rid of the first-push code -- I decided that it wasn't
  the right thing to do for per-dir merge-file processing.
- Improved the flist_find() function to make it a little more
  optimal.  The new code no longer needs the inline function
  flist_up().
- In clean_flist() we now set two new values in the flist struct:
  "low" and "high".  These are used by the new flist_find().
- Tweaked the output_flist() function to output each entry's
  flags and to output the directory-depth on the receiving side
  in place of the directory-root (which is still output on the
  sending side).