py-X: update to 0.15

(Spurred by the fact net/scapy expects the SVG support introduced back
in 2015.)

0.15 (2019/07/14):
  - text module:
    - introduce UnicodeEngine
    - MultiEngineText to express combined text data for TeX based engines and
      the new UnicodeEngine
    - Text and StackedText classes for simple typesetting operations on
      UnicodeEngine text
    - rename TexRunner and LatexRunner to TexEngine and LatexEngine
    - rename cls argument of text.set to engine (with fallback and
      deprecation warning in place)
    - improve error handling when input cannot be encoded by texenc
    - add support for virtual fonts in virtual fonts
    - font maps: treat font files without extension as Type 1 (to
      prevent warnings occuring especially with Minion or Libertine fonts)
    - fix UnicodeDecodeError for invalid character responses by TeX/LaTeX
      (reported by Gert Ingold)
  - new examples:
    - non-ASCII TeX encoding
  - t1font:
    - use integers in auto-guessed font descriptors to prevent an issue in pdftex
      (reported by Michael Hartmann)
    - fix typo: ItalicAngles -> ItalicAngle (thanks to Ross Moore)
  - graph.axis.texter:
    - unify exponential and mixed texter to default texter
    - use MultiEngineText in all texters (decimal, default, factional)
  - pdfwriter, pswriter, svgwriter:
    - removed underscore in  PS and PDF and SVG writer options strip_fonts,
      text_as_path, mesh_as_bitmap, mesh_as_bitmap_resolution
      (new: stripfonts, textaspath, meshasbitmap and meshasbitmapresolution)
      to prevent ambiquity with write_ prefixes.
    - Fix color output in SVG (reported by Michael Hartmann)
  - deformer:
    - Fix parallel deformer for empty normsubpaths (thanks to Michael J Gruber)
  - graph.style:
    - Use RGBA instead of ARGB in the bitmap fallback of graph.style.density
      Fix saving SVG as supported modes are limited (thanks to Michael J Gruber)
  - pattern:
    - inject default linewidth (reported by Michael J Gruber)
  - version control:
    - switched to git on 2018/07/16 with main repository on GitHub

0.14.1 (2015/11/02):
  - distribution:
    - upload to PyPI (including old releases)
    - remove old releases from sourceforge
  - text module:
    - fix load_def message parser (reported by Mico Fil坦s)
  - normpath:
    - fix intersect with empty normsubpaths (bug #62, thanks to Florent Hivert)

0.14 (2015/04/30):
  - new svgwriter module:
    - complete SVG output
    - SVG font output disabled by default due to missing support by
      most browsers, fallback by rendering fonts as paths
  - new svgfile module:
    - SVG reader
    - unparsed mode: embedd svg in other svg
    - parsed mode: supports reading paths (including styles,
      tranformations, etc.) into a PyX canvas
  - bitmap module:
    - using bytes in image type conversions and channel extraction
  - color module:
    - fix grey class
    - fix rgb css binary issue and short code index error
  - epsfile module:
    - fix parsing of bounding box
  - text module:
    - no end of pages test when no dvi is created at all
    - add chroot config option needed to use a chrooted TeX installation
  - graph module:
    - add xy12axesat feature to graphxyz
  - canvas module:
    - fix clipping and transformation applied together
    - provide _repr_svg_ in canvas for use by IPython
    - new constructor argument ipython_bboxenlarge
  - deco module:
    - remove shortcut for ornaments only to not skip global styles


(gutteridge)