bugfix: moving "invalid.h" down to "bits" broke autoconf

utility, invalid and traits moved to bits

UNDIRGRAPH_TYPEDEFS => UGRAPH_TYPEDEFS

The graph adadptors can be alteration observed.
In most cases it uses the adapted graph alteration notifiers.
Only special case is now the UndirGraphAdaptor, where
we have to proxy the signals from the graph.

The SubBidirGraphAdaptor is removed, because it doest not
gives more feature than the EdgeSubGraphAdaptor<UndirGraphAdaptor<Graph>>.

The ResGraphAdaptor is based on this composition.

Some classes assumed that the GraphMaps should be inherited
from an ObserverBase. These classes parents replaced with
DefaultMap which cause that the graph maps should not be
inherited from the ObserverBase.

Traits for alteration notifiers
SplitGraph is temporarly deleted

Bug fix

Default constructor which allocates empty graphs

An additional simplier interface for static size graphs.
Node operator()(int) for getting node by index
int index(Node node) for getting index by node

Bug fix

Bug fix

Bugfix

ListBpUGraph

Little bugfixes, spellchecks and improvements

Renaming to be convient to the naming of the adaptors
Concept checking of the ugraph adaptors

Mergeing extendermerge branch
Changes:
the extender system
resize for static size graph
UGraphExtender => UndirectGraphExtender
UGraphExtenders with changed meaning
Some UGraphExtender /SubUGraphExtenders, DirectUGraphExtender/
GridGraph => GridUGraph
radix sort to ansi compatible