[WIP] Parse content-line as text instead of just .*

[branch14]

This PR is the successor of #27.

The goal of this PR is to enable the EBNF parser to parse details in the content after a headline, e.g. links, timestamps, …

Closes #26 Closes #30

• [x] Update parser tests
• [x] Update transformers to return :raw along with :ast
• [x] Update transformer tests
• [x] Update core tests

[branch14]

@schoettl Changing transform to return the desired output came with a slew of other changes:

• transform is basically completely rewritten.
• parser/org rewritten to make raw available during transformation. (insta/span, which you suggested, works nicely)
• render rewritten to work with the new structure. (Rendering is still very basic, though.)
• core-test now lists all files for which a complete round-trip (parsing, transforming, rendering) is implemented. (Spoiler: only the most basic file, yet)
• integration.section-test is a first example of a feature based structure for tests.

Fun fact: I think we touched completely distinct files in this shared PR.

Is it ok, if I hand the PR back to you?

[schoettl]

Nice! I'll look into it soon!

Is it ok, if I hand the PR back to you?

Perfect, thank you :)