One structure for states is enough, even though theoretically

One structure for states is enough, even though theoretically
there are LR(0) states and LALR(1) states.
* src/lalr.h (state_t): Remove.
(state_table): Be state_t **, not state_t *.
* src/state.h (core, CORE_ALLOC): Rename as...
(state_t, STATE_ALLOC): this.
Add the LALR(1) members: shifts, reductions, errs.
* src/LR0.c (state_table): Rename as...
(state_hash): this, to avoid name clashes with the global
`state_table'.
* src/print_graph.c, src/LR0.c, src/LR0.h, src/conflicts.c
* src/lalr.c, src/lalr.h, src/output.c, src/print.c: Adjust.