v0.9.2

• fix a caching bug, which was a regression in 0.9.0 (issue #63)
• update license attribute in package.json as required by npm
  Thanks to Peter deHaan
• construct GMT times used in tests in a more robust way
• fix a bug calculating week numbers (issue #56)
  Thanks to Alexandr Nikitin
• warn about possible misuse of %:: or %::: modifiers