7.0.0

• Changed: minimum PHP version is now 7.0
• Changed: Added type hints and return types
• Changed: Moved extended DOM classes to FluentDOM\DOM\*
• Changed: FluentDOM\Nodes\Creator to FluentDOM\Creator
• Changed: Moved internal classes into FluentDOM\Utility
• Removed: Document::find() and Element::find()
• Fixed #70: FluentDOM\Query::get($position) should return a node
• Fixed #73, FluentDOM\Creator forgets namespaces
• Added #73: FluentDOM\XMLWriter::collapse() collapse DOM nodes
• Added #74: FluentDOM\XMLReader::attachStream() attach stream to read from