An SVN::Dump object represents a Subversion dump.

This module follow the semantics used in the reference
document:

* A dump is a collection of records (SVN::Dump::Record objects).
* A record is composed of a set of headers (a SVN::Dump::Headers
  object), a set of properties (a SVN::Dump::Property object) and
  an optional bloc of text (a SVN::Dump::Text object).
* Some special records (delete records with a Node-kind header)
  recursively contain included records.
