Removed the NodeList struct as it only had a "first" field and didn't
really serve any purpose outside of that. ParseNodes() now just returns
a pointer to the first Node.
- Parse code blocks that are wrapped sets of three backticks.
- Added a TT_TRIPLEBACKTICK token.
- Added a length field to the Token struct.
- Added an error node.
- Cleaned up some file read code.
- Fixed the header raw text (don't reuse the same buffer for each node).
Fixed parsing the tokens so it actually worked. Only headers are
currently implemented, but header nodes are now properly parsed and
everything else is properly ignored.
- Get the input filename from the command line
- Added in a bunch of checks to avoid segfaults
- Added some more debug info in places