moved things around, (almost) everything is in datalog.ml{,i}.
Additional modules are Ast, Parser and Lexer.
the API is simpler, it offers hashconsing, does not expose substitutions, and
most importantly exposes a proper term/literal disjunction;
implementation changes, with hashtables everywhere (no comparison),
no hashconsing of symbols by default;
the parser returns an Ast, which can then be transformed into proper structures
removed datalog/ dir
finished update (Const no longer needed);
use metadata of lexbuf in lexing/parsing to report errors (easier)