Remove unneeded lifetimes
Fixup makefile for dependencies
Update boxed traits due to upstream changes
Fix warnings in expressions
Fix warnings in xpath
Fix warnings in axis
Fix warnings in xpath-tokenizer-test
Fix warnings in xpath-expression-test
Fix warnings in xpath-{disambiguator,deabbreviator}-test
Add a constructor for ExpressionEqual
Mark XPathValue methods public
Port the basics of the XPath parser

Only numeric literals and equality operations are currently supported
Support basic math and relational operations
Add base set of XPath functions
Parse string literals, function calls, and variable references
Parse And and Or expressions
Build docs for both crates
Parse union expressions
Move nodeset macro to the document crate
Add the node-test objects