v0.1.2

• Added support for order references (1b36e19, c30e543, 9083535)
• Added VAT exemption reasons (6f4f711)
• Improved documentation (4a5069f, 74a1c8d)
• Fixed invoice end date in UBL exports (cc81153)
• Fixed VAT rate type (fdb526b)
• Used floats for line quantities (1939291)
• Fixed paid and rounding amounts being ignored (04333e4)