Fix a bug requesting back/front cell of a face during mesh modification

Comment unfinished parts of inmost in AdaptiveMesh

Update elasticity example in Examples/ADMFD

Add algorithms to split faces and to glue faces of the mesh (for tests
with MFD elasticty)

thread_private class for static OpenMP objects acts as iterator

EndModification do not unnecessarily delete orphan elements

Fixed Face::getNodes behaviour inside BeginModification and
EndModification region (same fix as in andre_brench)

Added template access functions for AbstractEntry class, allows to get
(matrix of) values, unknown indices or unknowns themselves depending on
template parameter

Examples/OldDrawGrid:
* Adjustments for svg output of color gradient in color bar (previously
was not properly working in Inkscape)
* Preparations for isosurface extraction code

Fixes for mesh modification algorithms

A lib for general adaptive mesh

Fix a bug in Face::FixEdgeOrder.

Behavior change for Destroy function: it deletes only hidden adjacent
elements of hidden element.

Fixed bug in Edge::SwapEnds.

Added Mesh::MarkerComparator to sort elements according to marker.

Removed local ctest configuration and one example.

Modified stencil expression and variable for more comfortable use.

Replaced code of newer C++ standard in xml.cpp.

Modified functions for adjacency retrieval to accept private markers in
parallel shared run.

Fix for possibility of race condition in point-to-point MPI
communications.

Fixes for warnings produced by clang.

Restored OctreeCutcell example;
Added FixEdgeOrder, CheckEdgeOrder algorithms to check of consistency of
2d elements;
Element::Connect now uses FixEdgeOrder for faces;
Automatic grid dimension detection for vtk;
Fixed bug that sets may contain invalid links to elements even after
ApplyModification;
Corrected condition estimator in ddpqiluc;
Switched off pseudoinverse in bicgstab(l) since svd algorithm is bad.

Fixes for gcc and intel compilers.
gcc-4.1 clean with -Wall -Wextra
intel 11.1 clean with -Wcheck -w1
msvc2010 gives one unrelated warning

Huge update involving update of underlying data representation and
elements management. Different interaction with iterators. New
ElementSet representation.  Some annotation for documentation is added.
New data structures. Examples require update. (check
examples/CMakeLists.txt)

Moving connections, markers, geometric type, sparse data from Storage
class to TagManager class by using standard handling of mesh data.

Retrieval of elements by markers;
Introduced options for loading of files;
Fixed issues saving vtk format when not all topological tests are
active;
Introduced Connect / Disconnect functions for manipulations with mesh;
DrawGrid example can now visualize array of entered cells/faces for
debug purposes;
OldDrawGrid example demonstrates fast interactive mesh slicing and
onscreen element picking.