3.28.0

- [featureVars] Added experimental module to build ``FeatureVariations``
  tables. Still needs to be hooked up to ``varLib.build`` (#1240).
- [fixedTools] Added ``otRound`` to round floats to nearest integer towards
  positive Infinity. This is now used where we deal with visual data like X/Y
  coordinates, advance widths/heights, variation deltas, and similar (#1274,
  #1248).
- [subset] Improved GSUB closure memoize algorithm.
- [varLib.models] Fixed regression in model resolution (180124, #1269).
- [feaLib.ast] Fixed error when converting ``SubtableStatement`` to string
  (#1275).
- [varLib.mutator] Set ``OS/2.usWeightClass`` and ``usWidthClass``, and
  ``post.italicAngle`` based on the 'wght', 'wdth' and 'slnt' axis values
  (#1276, #1264).
- [py23/loggingTools] Don't automatically set ``logging.lastResort`` handler
  on py27. Moved ``LastResortLogger`` to the ``loggingTools`` module (#1277).
Release 3.28.0
4 files changed