Change templates and fonts.
- Templates are always strings of data, parsed as EDn
- Fonts are passed around as a regular map

Both are part of a `context`, added to the text processing.
WIP: Major refactoring.
- Extract context object to contain fonts, templates, and basically
  everything.
- Add IO for creating the documents.
Actually add pages to document...
Comment some test statements.
Handle page breaking paragraphs across pages.