Added support for native Nokogiri nodes

Support the use of Nokogiri nodes when passed directly into the lambda
function for the getter.
Removed byebug ref
Merge branch 'master' of https://github.com/shirren/representable into cdata
document how to use a custom Binding to generate CDATA. if this is useful for many others, we can think about moving that into a core Binding with both serialize and deserialize support. closes #97.