Log Message:
Changes 4.55:
Some internal (non-API) routines to estimate the condition of
the basis matrix were added. These routines are mainly intended
to be used by the simplex-based solvers.

Two open modes "a" and "ab" were added to GLPK I/O routines.

Minor bug was fixed in the solver glpsol (command-line options
--btf, --cbg, and --cgr didn't work properly).

A serious bug was fixed in a basis factorization routine used
on the dense phase. (The bug might appear only if the number of
rows exceeded sqrt(2**31) ~= 46,340 and caused access violation
exception because of integer overflow.)

Two API routines glp_alloc and glp_realloc were documented.

Translation of the document "Modeling Language GNU MathProg"
to Spanish was included (in LaTeX and pdf formats).