0.8.0

• Added DecimalValue::getTrimmed.
• Added UnboundedQuantityValue.
  • QuantityValue extends UnboundedQuantityValue.
  • QuantityParser returns UnboundedQuantityValues instead of always guessing an uncertainty
    interval.
  • QuantityFormatter also accepts UnboundedQuantityValues.
• QuantityParser defaults to ±0.5 instead of ±1 when asked to guess an uncertainty interval, e.g.
  1~ becomes 1±0.5.
• QuantityFormatter does not round any more when the value is rendered with a known uncertainty
  interval.
• Fixed rounding algorithm in DecimalMath (rounded 1.45 to 2 instead of 1).
• DecimalValue constructor optionally accepts strings with no leading plus sign.
• Removed QuantityValue::getSignificantFigures.
• Removed QuantityValue::newFromDecimal (deprecated since 0.1).
• The $vocabularyUriFormatter parameter in the QuantityFormatter constructor is not nullable any more.