GitLab

Updated the code back-end to produce the same positions as ocamlyacc and the table back-end, in principle.
This involves:
1- moving the [endp] field (when it exists) to offset 1 in every stack cell,
   so it can be found when reducing an epsilon production;
2- creating a sentinel cell with an [endp] field at offset 1;
3- changing the code for epsilon productions to read the [endp] field in the
   top stack cell.

Updated [Invariant] with the constraint that an end position must exist on top of the stack whenever an epsilon production is about to be reduced.

Updated the table back-end to properly initialize the position in the sentinel cell at the bottom of the stack.
This requires changing the function [start] in the incremental API to take a position.
Updated the doc and demos.

computation in symbol_start_pos and get positions that match Menhir's.

takes its start and end positions to be the end position stored in
the top stack cell.

built yet.

Should fix the previous code, which was perhaps broken.

In the previous version, the redefinition of $(libdir) was ineffective when we were called from opam, which overrides $(libdir) from outside.