code: protected void addWatch(final int lit, final int blit, final boolean binary, final CLClause clause) {
          watches(lit).push(new CLWatch(blit, binary, clause));
      }
docs: Adds a new watcher for a given literal.
  @param lit    the literal
  @param blit   the blocking literal
  @param binary indicates whether it is a binary clause or not
  @param clause the watched clause