* View Large Files Improved

An Emacs mode that allows viewing files in chunks.  This is a fork
that builds on the bare bones GNU ELPA vlf.el.  It adds the following
improvements:

- regular expression search on whole file (in constant memory
  determined by current batch size)
- chunk editing (if size has changed, saving is done in constant
  memory determined by current batch size)
- options to jump to beginning, end or arbitrary file chunk
- ability to jump/insert given number of batches at once
- newly added content is acknowledged if file has changed size
  meanwhile
- vlfi is added as an option when opening large files

* Known issues

- When chunk starts with only part of multi-byte character, encoding
  for this chunk is clobbered visibly, don't edit/save in such case.
  Workaround is to move back to the first non-clobbered chunk and
  enlarge batch size until this chunk comes into range.