pymusicxml 0.6.0

Added

• StartOctaveLine / StopOctaveLine spanners, which emit a proper <octave-shift> element (an "8va"/"8vb"/
  "15ma" line with a dashed line and terminal hook). Renderers draw these natively, unlike a generic dashed
  <bracket> faking an octave sign.

Fixed

• Non-italic text annotations now write font-style="normal" explicitly, so readers that
  italicize <words> by default (e.g. Verovio) render them upright as intended.
• Notes now write an explicit <accidental> glyph, not just the <alter> pitch, so sharps,
  flats, and naturals show up in readers that don't infer them. Which accidental is drawn
  follows standard measure spelling: repeats within a measure are hidden, and the key
  signature and ties into the note are respected. (This also paves the way for a possible
  future feature of allowing different accidental spelling policies, such as showing accidentals
  on every note regardless of context.)
• Tied notes spanning three or more segments now emit their tie elements stop-before-start,
  fixing readers that drew one long tie across the whole group instead of separate ties.
• A note tied across a barline now carries its accidental as a hidden <accidental>, so
  readers that resolve pitch from the written accidental keep the tie instead of dropping it.
  (Verovio again, grrr...)