Entirely rework cycle canceling algorithms (#180)

- Move the cycle canceling algorithms (CycleCanceling, CancelAndTighten)
into one class (CycleCanceling).
- Add a Method parameter to the run() function to be able to select
the used cycle canceling method.
- Use the new interface similarly to NetworkSimplex.
- Rework the implementations using an efficient internal structure
for handling the residual network.
This improvement made the codes much faster.
- Handle GEQ supply type (LEQ is not supported).
- Handle infinite upper bounds.
- Handle negative costs (for arcs of finite upper bound).
- Extend the documentation.

EXTRA_DIST += \

	tools/CMakeLists.txt

if WANT_TOOLS

bin_PROGRAMS += \

	tools/dimacs-solver \

	tools/dimacs-to-lgf \

	tools/lgf-gen

dist_bin_SCRIPTS += tools/lemon-0.x-to-1.x.sh

endif WANT_TOOLS

tools_dimacs_solver_SOURCES = tools/dimacs-solver.cc

tools_dimacs_to_lgf_SOURCES = tools/dimacs-to-lgf.cc

tools_lgf_gen_SOURCES = tools/lgf-gen.cc