Rework Network Simplex
Use simpler and faster graph implementation instead of SmartGraph

Remove a faulty include from elevator.h

Backport hg commit [81d40f1c850c] (ticket #197)

Backport hg commit [52c04a2a652c] (ticket #197)

Various improvements in NetworkSimplex.

- Faster variant of "Altering Candidate List" pivot rule using make_heap
instead of partial_sort.
- Doc improvements.
- Removing unecessary inline keywords.

Improved constructors for min cost flow classes
Removing the non-zero lower bounds is faster

Improve tree update procedure in NetworkSimplex
The new method updates a smaller subtree (fixing a bug) and shifting the
potentials with a costant value.

Backport doxygen options for version 1.5.7 from [9194a12c52e6]

Adapt the doc generation to the hg repo

Major improvement in the cost scaling algorithm

- Add a new variant that use the partial augment-relabel method.
- Use this method instead of push-relabel by default.
- Use the "Early Termination" heuristic instead of "Price Refinement".

Using the new method and heuristic the algorithm proved to be
2-2.5 times faster on all input files.

Bug fixes is HaoOrlin and MinCostArborescence

MinCostArborescence
- proper deallocation
HaoOrlin
- the target needn't to be the last in its bucket
- proper size of container (if each node starts in different buckets initially)

Add missing pointer initializing in min cost flow classes

Fix _setCoeff

Bug fix in min_cost_flow_test.cc

Doc improvements