[CHANGES]

• Renamed distribution and timer reporting methods to more clearly
  convey their operation; now named ->report_distribution and
  ->report_timer
  
• Optional name prefix in Collector to simplify use in modules
  
• Use metric handle (combined with prefix) if no other name supplied
  
• Nicer API for supplying label values to reporting methods
  
• Check that reported label names match the declared names
  
• Support non-strict mode where metrics are lazily registered when
  first reported
  
• Added Metrics::Any::Adapter::Tee
  
• More flexible parsing of METRICS_ANY_ADAPTER variable