[docmaker] Recognise URLs.

* src/tools/docmaker/tohtml.py (re_url): New regular expression.
(make_html_para): Use it.
[doc] Fix hyperlinks.
* builds/freetype.mk (dll): Remove target.

Problem reported by Jörg Günnewig <joerg.guennewig@googlemail.com>.
[docmaker] Remove unused functions.

* src/tools/docmaker/content.py (DocMarkup.get_start,
DocBlock.get_markup_name): Removed.
* src/tools/docmaker/tohtml.py (html_quote0, dump_html_code,
HtmlFormatter.make_html_words): Removed.
[docmaker] Code shuffling.

* src/tools/docmaker/tohtml.py (re_url): Move regexp...
* src/tools/docmaker/sources.py: ... to this file.
[cff] Add `darkening-parameters' property.

* include/freetype/ftcffdrv.h: Document it.

* src/cff/cffdrivr.c (cff_property_set, cff_property_get): Handle
`darkening-parameters' property.

* src/cff/cf2font.h (CF2_FontRec): Add `darkenParams' array.

* src/cff/cf2font.c (cf2_computeDarkening): Add `darkenParams'
argument and use it.
Update all callers.

* src/cff/cf2ft.c (cf2_decoder_parse_charstrings): Copy
`darken_params' values.

* src/cff/cffobjs.h (CFF_DriverRec): Add `darken_params' array.

* src/cff/cffobjs.c (cff_driver_init): Set default values for
`darken_params'.
[cff] Add darkening limit to `darkening-parameters'.

* src/cff/cffdrivr.c (cff_property_set): Add check.
* src/winfonts/winfnt.c (FNT_Load_Glyph): Fix bitmap width guard.
* docs/CHANGES: Updated.
One more update to `CHANGES' file.
[sfnt] Fix documentation of `tt_face_get_metrics'.

Problem reported in Savannah bug #39383.
Merge branch 'master' of git://git.sv.nongnu.org/freetype/freetype2