added recommendation on specifying item price as amountIncVat and vatPercent to 5.1
documented required setInvoiceDistributionType() method
Merge branch 'develop' of https://github.com/sveawebpay/php-integration into develop
improved documentation on WebPayAdmin::XXXOrderRows-functions
added missing unit tests of validation and integration tests for functionality for WebPayAdmin::XXXOrderRows-functions
updated gh-pages documentation
Merge branch 'backported_fixes_to_deliverOrderRows_from_INTG-565' into develop