Various doc improvements for graph adaptors (#67)

- Add notes about modifying the adapted graphs through adaptors
if it is possible.
- Add notes about the possible conversions between the Node, Arc and
Edge types of the adapted graphs and the adaptors.
- Hide the default values for template parameters (describe them
in the doc instead).
- More precise docs for template parameters.
- More precise docs for member functions.
- Add docs for important public typedefs.
- Unify the docs of the adaptors.
- Add \relates commands for the creator functions.
- Fixes and improvements the module documentation.

Add creator functions for Residual and Residual::ResidualCapacity (#67)

Various bug fixes and code improvements in adaptors.h (#67)

- Fix UndirectorBase::nodeNum().
- Fix UndirectorBase::findEdge().
- Fix OrienterBase::addArc().
- Fix OrienterBase::findArc().
- Improve SplitNodesBase::findArc().
- Add missing notifier() function in UndirectorBase.
- Add missing typedefs for maps (conform to the ReferenceMap concept).
- Add some useful typedefs for graph adaptors.

Add missing const keywords (+ remove misleading ones) (#67)

Avoid warning in adaptors.h (#67)

Fix the usage of tags in adaptors.h (#67)
There are separate tags for arcs and edges now.

Merge

Update to 2009 plus whitespace unification

Rename counterSort to stableRadixSort

Doc improvements and source unification in radix_sort (#72)