Complete Rewrite

[Simre1]

Complete Rewrite of the parser with some bits taken out of the old parser. The old parser had some weaknesses:

• Overly complex paragraph parser
• Whitespace sensitive bits are parsed with lots of backtracking and is brittle
• Tag parsing system is cool but the extensibility is not really needed

The rewrite tries to fix these issues and will follow the layer based implementation plan described within the neorg specification.