Alter example to reflect that IDs must always start with upper case
Remove simple system test game
Subtantial grammar change: Removed system option

Remove system option - A single DGDL description now describes a
single dialogue game. Shifts & embeddings are still achieved by
careful formulation of rules rather than requiring a complex of
games
Remove 'system' clause from EBNF grammar
Make grammar name match filename
Second test description - includes rules
Include regulations & interactions clauses
Interpolate EBNF as comments into ANTLR grammar for clarity