Whitespace changes

Convert from space indentation, back to tab indentation, so others can
configure their development environments to their liking.
Remove '--no-error-on-compression-fail' argument

This argument is no longer needed and as such, causes flac-1.3.0 users
(non-git), and below to fail when verifying FLAC files during
compression.

flac-1.3.0 (and below):
  This argument doesn't exist, and the failure this is meant to prevent
  doesn't exist, so this argument is removed.

flac-1.3.0 (git):
  Shortly after the release of 1.3.0, developers added in the above
  option, '--no-error-on-compression-fail'.  This was meant to prevent
  the encoder from exiting with a non-zero exit code, due to new
  changes.

  The changes were to error on compression if the ratio was >1.000,
  since compression side of the encoding actually didn't result in any
  gain (failure).

  The above option would force the encoder to give a 0 exit code, making
  the error a "warning" since the encoding was successful, just not the
  compression ratio (ie, not a smaller file size).

  The developers soon realized the above option wasn't all that great,
  and created a new one called '--error-on-compression-fail'.  This is
  to "opt-in" to the non-zero exit code.  Now, if the ratio from
  compression is >1.000, a warning message will display but the exit
  code will be 0, by default.  Using the new argument, people can opt to
  have a non-zero exit code.  The original argument is still maintained
  for compatibility (doesn't do anything right now).

  Going forward, redoflacs is omitting the above two options, as this is
  not considered an error when verifying FLAC files.

  Users running a version of FLAC 1.3.0 (from git) may have issues if
  it's a version which has the first argument, but not the second. Since
  the FLAC version in question is development stage software, it's
  unreasonable for redoflacs to support it, since the way going forward
  in FLAC has been defined.

To summarize, the removal of '--no-error-on-compression-fail' argument
allows redoflacs to function appropriately for all users of FLAC
(non-git), as is intended.
Greatly speed up '_retag_*' functions

Partial revert of: a537a28300a1de0cfc5e15c8bb4bbd850dd03911

_retag_analyze() and _retag_apply():
  In the previous commit (mentioned above), the way stored tag fields
  were sent to 'metaflac' resulted in a massive slowdown of analyzing
  tags and setting them.  This was necessary, though in order to have
  'metaflac' properly handle whitespace in VORBIS COMMENT fields.

  This new commit reverts to sending a printed array of tag fields
  directly to 'metaflac', like before, only now, the quoting of the tag
  fields is done properly in an array, to allow 'metaflac' to interpret
  any and all tag fields, including whitespace.