6.5.0: Enter PHP 5.5

• Heads up: Bumped minimum PHP version required to PHP 5.5. See PR #4
  (@thekid)

6.4.3: Date token in Patternlayout

• Fixed util.log.LogObserver not accepting LogCategory instances - @thekid
• Implemented PR #1: Patternlayout: %d for dates - @thekid
• Code QA: Adopt to newest unittest coding standares - @thekid

6.4.2: Extract from core

• Heads up: Split library from xp-framework/core as per xp-framework/rfc#301
  (@thekid)