Fix documentation issues (#314)

Fractional matching initialization of weighted matchings (#314)

Add fractional matching algorithms (#314)

General improvements in weighted matching algorithms (#314)

- Fix include guard
- Uniform handling of MATCHED and UNMATCHED blossoms
- Prefer operations which decrease the number of trees
- Fix improper use of '/='

The solved problems did not cause wrong solution.

Merge bugfix #356 to branch 1.1

Fix multiple execution bug in weighted matchings (#356)

This chgset also redoes the fix of [28c7ad6f8d91] and its backpont to 1.1,
[268a052c3043].

Add doc/references.dox to .hgignore

Replace figure at matching doc #348

The original bibartite_matching.eps is kept for future use.

Rename min mean cycle classes and their members (#179)
with respect to the possible introduction of min ratio
cycle algorithms in the future.

The renamed classes:
- Karp --> KarpMmc
- HartmannOrlin --> HartmannOrlinMmc
- Howard --> HowardMmc

The renamed members:
- cycleLength() --> cycleCost()
- cycleArcNum() --> cycleSize()
- findMinMean() --> findCycleMean()
- Value --> Cost
- LargeValue --> LargeCost
- SetLargeValue --> SetLargeCost

Fix gcc 3.3 compilation error (#354)

gcc 3.3 requires that a class has a default constructor if it has
template named parameters. (That constructor can be protected.)