[xmlunit/xmlunit] f0ffe6: add DifferenceEvaluator that ignores XML Prolog

[GitHub <no...@gi...>]

  Branch: refs/heads/master
  Home:   https://github.com/xmlunit/xmlunit
  Commit: f0ffe6bced1517befd1eb73690db4a50dace4458
      https://github.com/xmlunit/xmlunit/commit/f0ffe6bced1517befd1eb73690db4a50dace4458
  Author: Stefan Bodewig <ste...@fr...>
  Date:   2016-03-19 (Sat, 19 Mar 2016)

  Changed paths:
    M xmlunit-core/src/main/java/org/xmlunit/diff/DifferenceEvaluators.java
    M xmlunit-core/src/test/java/org/xmlunit/diff/DifferenceEvaluatorsTest.java

  Log Message:
  -----------
  add DifferenceEvaluator that ignores XML Prolog

This mimics the behavior of XMLUnit 1.x and may sometimes ease the
transition. See #59.