Changeset 2619:30fb4d68b0e8 in lemon-0.x for test

Improve network simplex algorithm

• Remove "Limited Search" and "Combined" pivot rules.
• Add a new pivot rule "Altering Candidate List".
• Make the edge selection faster in every pivot rule.
• Set the default rule to "Block Search".
• Doc improvements.

The algorithm became about 15-35 percent faster on various input files.
"Block Search" pivot rule proved to be by far the fastest on all inputs.