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.

if WANT_TOOLS

bin_PROGRAMS += \

	tools/dimacs-to-lgf

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

endif WANT_TOOLS

tools_dimacs_to_lgf_SOURCES = tools/dimacs-to-lgf.cc