Improvements in groups.dox (#188)

- Unify the notations used for formulas.
- Add 'namespace lemon {...}' to simplify the references.
- Improved doc for algorithm groups.
- Extend the doc of the "shortest path" and "minimum cost flow" modules.

Doc improvements for Bfs, Dfs, Dijkstra (#185)

- More precise references to overloaded member functions.
- Hide the doc of the traits class parameters.
- Better doc for named groups.
- More precise doc for the case of multiple sources in Dfs.

Merge

Improve test file for Circulation (#175)

- Bug fix: add a missing #include.
- Add compile test for various functions and named parameters.
- Use a smaller digraph with lower bounds.
- Test eight instances instead of two.
- Remove the doc that was for the demo file.

Many doc improvements for Circulation (#175)

- More precise doc for members.
- Several doc fixes.
- Add doc for public types.
- Better formulations.
- Add useful notes to the problem description.
- Use supply instead of excess in the doc.
- Hide the doc of the traits class parameter.
- Use \tparam for template parameters.

Def->Set change in lemon/circulation.h

Transform circulation demo to test

Port Circulation from svn -r3516 (#175)
Namely,
- port the files
- apply the migrate script
- apply the unify script
- fix the compilation
- strip the demo input file
- break long lines

Merge

Remove DijkstraWidestPathOperationTraits (#187)