Please add newline character support.

[cpardilla]

Wonderful project. The only problem I have encountered so far it's the lack of support for the newline character (\n) when trying to replace expressions. It seems to take it literally (that is, I get the literal "\n" character and not a newline as expected) and I don't know how to produce a true newline when getting the replaced content (or I am not doing it correctly).