Added a few TODO items.
Renamed TODO before converting to reStructuredText.
Reformatted TODO as reStructuredText.
Renamed Grammars.fs to Grammars.Appel.fs.
Created Grammars.Grune.fs to hold example grammars from Dick Grune's "Parsing Techniques, A Practical Guide".
Added some grammars from "Parsing Techniques, A Practical Guide" so they can be used as test cases for grammar optimizations (when we implement them).
Moved the relation-computing code from the Lalr1 module into a new file (Relation.fs) so it can be used to implement algorithms in other modules too.
Fixed namespacing issues caused by splitting the grammars over multiple modules/files.