Update textproc/heirloom-doctools to 160217.
Patch provided by Carsten Kunze via pkgsrc-wip and discussed with me via private
emails.

Changes:
Release 160217
==============

2016-02-17
    tbl:  Invalid memory access bug fixed.  (When testing if a
    line starts with '_' or '=' it did not check if the string is
    empty.)

2016-02-16
    .tr bugfix:  When the first character given to .tr was un-
    known, all character translations had been done wrong.

2016-02-11
    tbl troff bug fixed:  Height of table had been calculated
    wrong.  This could lead to graphics artifacts if a table is
    at page bottom.

2016-02-10
    Many changes to -man and -mdoc.  Heirloom's manual page for-
    matting is now quite compatible to groff.

2016-02-08
    Operator 'v' added for ".if".  (Some manpages using this.)

2016-02-02
    -ms: Macros .QS and .QE added.

2016-01-29
    Support for groff's notation \[uXXXX] added.

2016-01-26
    nroff: Use of new names for .char now possible.  (Up to now
    only names found in the tab file could be used.)

2016-01-01
    Spaces are now allowed in filenames of .cf, .fp, .lf, .nx,
    and .so requests.  The documentation stated that %20 could be
    used to escape spaces.  However this was not implemented.
    The implementation has now been changed to allow spaces by
    quoting the filename with '"'.  Additionally character codes
    up to 255 are allowed now in filenames.  (Bug reported by
    Jacob Parker (https://github.com/jacobp100).)

2015-12-23
    groff's operator ".if F <font>" added.

2015-12-18
    Support for groff's notation \[char<n>] added.

2015-12-10
    File system case-sensitivity issue fixed.  (Reported by Henry
    McGilton.)

2015-10-28
    Set previous font to current font in case of unknown font.
    This is the groff behaviour.  E.g. \fIfoo\fP \f(CWbar\fP blah
    did underline "blah" in AT&T nroff.

2015-09-23
    \n[.ns] implemented (had only been documented up to now).

2015-09-21
    Basic HTML support added.

2015-09-18
    Escape \I added (test if argument is a valid identifier).  \I
    is equivalent to groff's \A.

2015-07-14
    PDFMark: \X'SetBorderStyle' added.

2015-07-08
    Special groff compatibility mode for manual pages added which
    is enabled when register .g is set to 1.

2015-06-24
    .box bug fixed: .box did discard part of roff's state.

2015-06-22
    mm(7): .PGFORM added to allow line length change inside docu-
    ment.

2015-06-10
    .ie-.el bug fixed.  Up to now .ie-.el did not work fully re-
    liable in AT&T roff.  (Found during -mdoc debugging.)

2015-06-08
    mdoc: Macro Lb with library definitions for FreeBSD and
    NetBSD added.

2015-06-05
    nroff -T37 (default), -Tlp and -Tlocale: Display of pic(7)
    drawings implemented.

2015-06-04
    troff -Tpost: All font description files now uppercase (for
    use on case-insensitive file systems) and use of groff font
    names instead of traditional names now possible with .ft and
    \f.

2015-05-26
    Bugfix: nroff: Local motions had not been local (did stay in
    effect across line boundary).

    nroff: Request \D'l ...' added.

2015-05-02
    mdoc(7): .El: List type stack bug fixed.


(leot)