added forward declaration for make_*, moved doxygen documentation to forwards.hpp, added result_of::segment_handle forward declaration
added all_elements view to segmentation, added empty method for segment_info_t and segment_id_range_t (used for reference counting), erase(segment, element) now erases recursevely (erasing a vertex will erase all lines, triangles, ... referencing it)
using viennagrid::add(segment, element) instead of add_handle for segments
Added support for coboundary ranges on views (views might not be element-complete)
Added mark_referencing_elements, added erase_elements implementation for views
Coding style, added for_each for all elements of a mesh/segment
some more example for erasing element from segment
Added element deletion from view