Added sgs method to driver test
Fixed valgrind error
Updates for 64-bit matlab
Fixed stupid typo
prpack_igraph_graph: ignore negative or zero weights
Merge branch 'tamas' into fullmerge

Conflicts:
	matlab/pagerank.m
	matlab/pagerank_solver.m
	matlab/use_pagerank_solver.cpp
	matlab/utils.h
	prpack_base_graph.cpp
	prpack_base_graph.h
	prpack_csc.h
	prpack_driver_benchmark.cpp
	prpack_solver.cpp
	prpack_solver.h
Merge branch 'master' of https://github.com/ntamas/prpack into tamas
Merge branch 'tamas' of github.com:dgleich/prpack into tamas