XMLUnit.NET 2.8.0

This version contains a backwards incompatible change to the IPlaceholderHandler interface that is part of the experimental placeholders module: The Evaluate method now receives a variable number of string arguments in addition to the textual content of the element/attribute. This allows placeholders like ${xmlunit.matchesRegex(some\s*regex)}.

Only the placeholder package has been changed, all other packages are functionally identical to XMLUnit.NET 2.7.2.

• add a new ${xmlunit.isDateTime} placeholder
  PRs #31 and #32 by MilkyWare

• added a new ${xmlunit.matchesRegex(regex)} placeholder
  based on Java PR xmlunit/#178 by @Jazzyekim.