• Add elseif as an alias of elif for parity with Twig. Thanks kswedberg.
  Merge of #826.
• Add nunjucks env to express app settings as nunjucksEnv.
  Merge of #829.
• Add support for finding an object's "length" in length filter.
  Merge of #813.
• Ensure that precompiling on Windows still outputs POSIX-style path
  separators. Merge of #761.
• Add support for strict type check comparisons (=== and !===). Thanks
  oughter. Merge of #746.
• Allow full expressions (incl. filters) in import and from tags. Thanks legutierr.
  Merge of #710.
• OS agnostic file paths in precompile. Merge of #825.