Integrating dom4j with the fix for java.lang.ClassCastException:
org.dom4j.DocumentFactory cannot be cast to org.dom4j.DocumentFactory

See: https://github.com/stapler/stapler/pull/36

Integrated a bridge-method-injector that rebuilds the constant pool from
scratch.

Integrated the fix made in winp 1.20.

Documented this feature and integrated a newer version of Stapler.

I took the opportunity to reorder the content in the section, so that
the tree parameter becomes the main subject.

At this point, the depth parameter should be only used in a limited
circumstance, so it should be treated as such.