Extend parser to process implementation section

[hellola]

This will allow:

• Line numbers in the documentation to refer to the implementation.
• AOP features such as injecting tracing data to be added to the parser

Would be good to separate the parsing of the file and its processing for generating output. Currently this is tightly integrated and this makes it difficult to extend for additional features such as this.

[macite]

Requires the Parser to be extended to examine the implementation section. This could then be extended to add additional features to the code (tracing for example) more easily.
General parser updates could be included with this as the current model is a little difficult to understand / extend.