add gridgraph neighborhood creation and tests
renamed neighborhoodType() into borderType() (StridedScanOrderIterator, CoupledScanOrderIterator)
first version of gridgraph vertex and out-edge iterator
removed unused CoordinateMultiIterator
refactored StridedScanOrderIterator (now implemented in terms of CoupledScanOrderIterator)
removed unused MoveToScanOrderIndex
removed unused multi_gridgraph_vertex_iterator.hxx (now in multi_iterator.hxx)
added GridGraphNeighborIterator and test
added missing detail::
added GridGraphOutEdgeIterator and tests
added GridGraphEdgeIterator
added TinyVector methods subarray(), any(), all() and tests
added missing 'template' keyword
added MetaPow
added CoupledScanOrderIterator methods isValid(), atEnd(), improved getEndIterator() and tests
added GridGraphEdgeIterator and tests
first version of GridGraph
added TinyVector::unitVector() factory function and test
refactored/improved GridGraph and tests
added tests for all GridGraph iterators