v3.1.0

Added

• Added function isRange as a simple and clear way to check if a variable is a DateRange
• Added moment extension parseZoneRange to preserve timezone of start/end dates in a new range
• Added moment extension rangeFromInterval to create a range between a date and a specified interval

Changed

• Changed open-ended ranges to accept any falsy value (except 0)
• Changed add function: now has an option for adding adjacent ranges
• Changed README: tidied documentation examples

Fixed

• Fixed typo in README in method add
• Fixed webpack output path for webpack >2.3.0
• Fixed linter errors/warnings for development
• Fixed repository URLs in CHANGELOG