GLPK 4.60:

Some improvements were made in the primal and dual simplex
solvers to make the solution process more numerically stable.

An experimental long-step ratio test feature was added to the
dual simplex. On API level this feature is available thru the
GLP_RT_FLIP option. For glpsol it is available thru the options
--flip (for MIP) or --flip and --dual (for LP). This feature is
not documented yet.

Additional check was added to reject wrong solutions sometimes
reported by the PROXY heuristic.

A bug (memory leak) was fixed in the FPUMP heuristic routine.

The header sql.h was renamed to avoid conflicts with standard
ODBC headers.

(adam)