Resolve 'unused variable' warning

Revert an unintentional commit in r2933

xy -> dim2::Point

I forgot to remove the benchmarking part of code

UnionFind
Changing the representation of the union-find
it has the same running time but it takes just 2/3 space
! does not auto insert items /performance/

UnionFindEnum
Changing the interface - more convenient to UnionFind
Does not based on the stl data structures /it could be disadvantage/
=> does not use singular iterator assignment /not stl conform, but always work/
Just new iterator interface

MaxMatching + UnionFindTest
Using new iterator interface instead of the old

Some doc fix

Signaling alterations in BpUGraphs

New map type based on array map for debugging purpose

It checks multiple allocation and deallocation of map values and
some consistency.

todo:
clarification of debugging concepts
assertions - exceptions - debug
revision of attic/debug.h

motto:
testing is at least so important as coding

Bug fix in DescriptorMap
Avoiding the possibility of the memory leak

An easy avoiding of a bug

The functional interfaces are removed.
Better solution could be a reference counted core of the io interfaces

Now it is huge work so just write that:

GraphReader<ListGraph>(std::cin, graph).

Instead of:

graphReader(std::cin, graph).

Bug fix

Using abort() instead of exit(1)

If a program is aborted then the call stack can be analyzed with debugger.
The exit(1) does not provides that.