added get_*_data_on_* free functions
added changelogs for 1.1.0
ncell -> element, adapted to new interface
New section: type basics (how to define/instance types)
ViennaData -> Accessor concepts
ncell -> elements
Added overview on all available types
ncell -> element, adapted to new element types
added segmentation, ViennaData -> accessors
ncell -> element, added neighbour iteration, adapted to new coboundary iteration
update
Merge branch 'master' of github.com:viennagrid/viennagrid-dev

Conflicts:
	doc/manual/changelogs.tex