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.

lemon (0.5-1) unstable; urgency=low

  * Initial Release.

 -- LEMON Development Team <etik-ol@cs.elte.hu>  Tue, 14 Jun 2005 08:29:34 +0200