Fixed a typo in adjacent_triangles function name.
Function to list triangles in a graph (#584).

All triangles are listed. Not possible to list
triangles adjacent to a vertex. C docs is missing.
Stimulus: R supports post-processor functions now.
C: integer stack type added.
All simple paths from one source (#356).

R interface and C and R docs included.
Removed a printf (was never called) for CRAN checks.
FR layout: some speedup, removed 'width' and 'height' arguments.
FR layout works better with unconnected graphs now.
FR: removed an unneeded check for some minor speedup.
added interruption support to igraph_get_all_simple_paths()
Python: added Graph.get_all_simple_paths()
Readded support for rewritten 3d FR layout.
Merge branch 'develop' of github.com:igraph/igraph into develop
fix division by zero errors in Fruchterman-Reingold layout
Python: fix a crash in Graph.layout_fruchterman_reingold()
C docs for adjacenct triangles, listing triangles.
Merge branch 'develop' of github.com:igraph/igraph into develop
Bipartite projection detects invalid edges (#543).
R: fix 'simplify' argument of graph.formula (#586).
R: better names by crossing(), fixes #587.