v0.6.0

Highlights

• The Style struct has been "traitified". This supports Taffy's integration in Servo and generally makes Taffy more flexible. The
  Style struct still exists and implements the new traits so existing uses of Taffy will continue to work as before.
• The box-sizing style is supported
• Computed margins are output in Layout

Fixes

• Fix print_tree() when rounding is disabled (#680)
• Absolute Insets should be resolved against the container size minus border (#666)
• Fix flooring hypothetical_main_size by computed min size (#689)
• Fix flex line cross-size determination (#690)
• Fix panics in the grid algorithm (#691)
• Fix resolving flexible lengths (WPT css/flexbox-multiline-min-max test) (#692)
• Fix wrapping when a max main size style is present (#694)
• Fix case where Taffy allowed margins to collapse through an element when it shouldn't have (#695)

Added

• Legacy text align (for laying out <center> and <div align="..">) is supported
• Add is_table for block items (#701)
• Impl Debug and Clone for Cache (#688)
• Implement Debug and PartialEq for tree types (#697)