Added an explanation of what's in this directory.
Wrote more notes about project conventions.
Corrected some goofs.
Fixed more formatting goofs.
Added more info.
1. Explained more about the assumptions behind the parser.
2. Provided some hints for how to debug parser behavior.
3. Misc other small changes.
Merged branch 'doc-work' into 'develop'.
Merging documentation work from branch 'develop'.