v5.2.0

• Implemented much of the ParentNode mixin (Joris-van-der-Wel):
  • Moved children from Node to ParentNode, i.e., made it available on Document, DocumentFragment, and Element, but not other types of nodes.
  • Made children a HTMLCollection instead of a NodeList.
  • Implemented firstElementChild, lastElementChild, and childElementCount.
• Implemented the outerHTML setter. (@Joris-van-der-Wel)
• Fixed the outerHTML getter for <select> and <form>. (@Joris-van-der-Wel)
• Fixed various issues with window-less documents, so that they no longer give incorrect results or blow up in strange ways. You can create such documents with e.g. document.implementation.createHTMLDocument(). (@Joris-van-der-Wel)
• Fixed relative stylesheet resolution when using @import. (@dbo)