Changeset 710:8b0df68370a4 in lemon for doc/min_cost_flow.dox

Fix the GEQ/LEQ handling in NetworkSimplex? + improve doc (#291)

• Fix the optimality conditions for the GEQ/LEQ form.
• Fix the initialization of the algortihm. It ensures correct solutions and it is much faster for the inequality forms.
• Fix the pivot rules to search all the arcs that have to be allowed to get in the basis.
• Better block size for the Block Search pivot rule.
• Improve documentation of the problem and move it to a separate page.