Upgrade to jdom 2.0.6

    Fixes Issue 120 - Incorrect cloning of JaxenCompile ending up with variables shared between clones.
    Fixes Issue 127 - When Outputting content, getting a PrettyFormat Format, then setting it to "Preserve" does not preserve properly
    Fixes Issue 126 - While namespaces prefixes like "Xml" are discouraged, they are actually allowed (except "xml" and "xmlns" - case specific).
    Fixes Issue 128 - Third party Security audit revealed a few places which were vulnerable.
    Fixes Issue 129 - Java 8 introduces public sort method on List interface. This conflicts with protected sort on ContentList
    Fixes Issue 131 - JavaDoc fix
    Fixes Issue 134 - Upgrade Xalan to 2.7.2
    Fixes Issue 143 - Maven third party dependency versions
    Fixes Issue 136 - XMLReaders enum initializes all three members on first use (Non-validating, DTD, and XSD). This can be slow when not needed.
    Fixes Issue 138 - Non-Namespace Aware DOM constructs get Parsed OK by JDOM 1.x but fail on JDOM 2.x. Make JDOM 2.x look harder for undeclared prefixes.