MFC vtfontcvt improvements:

r267011: Make height and width optional arguments

  Now defaults to a 16x8 font size.  The height and width can be specified
  using -h and -w respectively.

r267012: Make the bold font optional

r267035: Use a hash to speed up glyph deduplication

  Walking a linked list of all glyphs to look for a duplicate is very slow
  for large fonts (e.g., for CJK character sets).  In my test the runtime
  for a sample 40000 character font went from just over 80 seconds on
  average to just over 2 seconds.

r267119: -w sets the width, not height

r267123: Support "GNU Unifont" format font data

  The GNU Unifont .hex format is a text file.  Each line represents one
  glyph and consists of a four-digit hex code point, a colon, and pairs of
  hex digits representing the bitmap.  By default an 8x16 font is assumed,
  with 16x16 double-width glyphs, resulting in either 32 or 64 hex digits
  for the bitmap.

  Our version of the file format supports comments at the top of the file
  to set the height and width:

  Each row of bitmap data is rounded up to byte width - for example, a
  10-pixel wide font uses 4 characters per row.

  See http://czyborra.com/unifont/ for more background on the original
  format.

r267126: Accept space after BITMAP in .bdf parser

  The Unifont BDF generator incorrectly adds a space after BITMAP, and
  and that error has been widely propagated.

r267173: use -h height and -w width args

r267298: Hide stats by default and improve error handling

  The font stats are interesting, but rather verbose.

r267301: Speed up bold glyph map deduplication

  Perform an O(n) deduplication pass over the bold maps at the end, rather
  than walking the normal map list to look for a duplicate glyph each time
  a bold mapping entry is added.

r267324: handle failure writing output font

r267337: move to usr.bin/vtfontcvt

  vtfontcvt is useful for end users to convert arbitrary bitmap fonts
  for use by vt(4).  It can also be used as a build tool, allowing us
  to keep the source font data in the src tree rather than uuencoded
  binaries.

  Reviewed by:  ray, wblock (D183)

r267366: Avoid leaking file pointer on error

  CID:          1222506, 1222505

r268022: Rename the WITHOUT_VT_SUPPORT knob to WITHOUT_VT

  The _SUPPORT knobs have a consistent meaning which differs from the
  behaviour controlled by this knob.  As the knob is opt-out and has not
  appeared in a release the impact should be low.

r268172: correct width calculation (.hex files and commandline)

r268948: Use the standard way of printing the usage string

r268949: Remove redundant return statement after errx

Also update vtfontcvt(8), based on inclusion in FreeBSD 10.1

Sponsored by:	The FreeBSD Foundation