This is a singleton class for parsing XML into a tree structure. How does this
differ from other XML tree generators? By using XML::Parser::Lite, which is a
pure perl XML parser. Using this module you can tree-ify simple XML without
having to compile any C.

Each node contains a "type" key, one of "root", "tag" and "data". "root" is the
document root, and only contains an array ref "children". "tag" represents a
normal tag, and contains an array ref "children", a hash ref "attributes" and a
string "name". "data" nodes contain only a "content" string.