split up MshEditor class

Gui/DataView/DirectConditionGenerator.cpp

Gui/DataView/GeoMapper.cpp

Gui/DataView/MeshValueEditDialog.cpp

Gui/DataView/MshLayerMapper.cpp

Gui/DataView/MshView.cpp

Gui/mainwindow.cpp

MeshLib/CMakeLists.txt

MeshLib/MeshEditing/ElementValueModification.cpp

MeshLib/MeshEditing/ElementValueModification.h

MeshLib/MeshEditing/removeMeshNodes.cpp

MeshLib/MeshEditing/removeMeshNodes.h

MeshLib/MeshSurfaceExtraction.cpp

MeshLib/MeshSurfaceExtraction.h

MeshLib/Node.h

Utils/MeshEdit/moveMeshNodes.cpp

Utils/MeshEdit/removeMeshNodes.cpp