update styles to reflect change in kbd macro HTML
make document parsing a discrete step, make Reader accessible as property on Document

- pull parsing out of Document#initializer and make it a discrete step
- don't parse Document on creation unless :parse option is true
- make Reader accessible as a read-only property on Document
- rewrite reader tests to use Reader created by Document
- optimize access to instance variables in Document#initializer
- use requested ERB implementation in TemplateConverter, add tests