run.py script updated, now enforcing memory limit
modified Makefile
use new Datalog version, that contains a functor to use any type we
want as datalog symbols. Update modules to use proper symbols directly in datalog.
require sequence as a submodule
require Jsonm and Uutf as libraries in makefile
Revert "require Jsonm and Uutf as libraries in makefile"

This reverts commit fd5c51d78993fe9b4eb911274e7e78cd77c3cba8.
compile and use the sequence submodule in Makefile
Sexpr small library, relying on Sequence
murmur hash on 31 bits
update of Sexpr module, with better printing (and it compiles)
apparently correct lexing and parsing
new target to build a library containing most modules of the prover
compile correctly with Sequence library; build binaries after lib because
otherwise ocamlbuild deletes them
do not use Marshal to serialize/deserialize the KB;
instead use the human readable format (allows to build symbols with hashconsing while
parsing, marshal cannot do that). Also added PBoundVar and PBind to patterns, so that they
more closely follow terms;
printing of patterns is now much better, with TSTP syntax, infix symbols, and correct
handling of De Bruijn variables *)
better error reporting in parser and lexer
bugfixes in printing of patterns;
printing theories and lemmas requires to print variables as symbols
forgot to import resource in run.py
fix statistics;
superposition condition must be checked on terms with the same offset;
same for demodulation
Big change: get hashconsing of clauses back for 2 reasons:
- it saves memory since less clauses exist
- it allows for easier management of parents/descendants clauses => much better orphan elimination
exported to Terms and Literals functions to close by quantifiers formulas/literals