rdf 0.1.0

`rdf` is a library for the [Resource Description Framework](https://www.w3.org/RDF/) (RDF) and [SPARQL](https://www.w3.org/TR/rdf-sparql-query/) implemented in Rust.
Documentation
// todo: implement

#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub struct Uri {
  uri: String
}

// todo
impl Uri {
  pub fn new(uri: String) -> Uri {
    Uri {
      uri: uri
    }
  }

  /// Returns the string representation of the URI.
  pub fn to_string(&self) -> &String {
    &self.uri
  }

  /// todo
  pub fn append_resource_path(&mut self, path: String) {
    // todo: check if URI ends with '/', if not add '/'
    self.uri.push_str(&path.to_string());
  }
}