A working Python interface.
Added sgs method to driver test
Fixed valgrind error
Updates for 64-bit matlab
Fixed stupid typo
Weighted PageRank.
Gaussian Elimination method created.
dos2unix everything
1. Change things to const.
2. Replace inv_num_outlinks with num_outlinks.
3. Create a help menu.
Note: these commits didn't seem to go through, so I'm compressing these into one =(.
added partial support for igraph graphs; WIP
preparing prpack_solver to handle graphs coming from igraph
bugfixes in prpack_igraph_graph
Made igraph optional
Fix for normalized weights WIP
Fixed weighted code
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