Added degree distribution, size, and edge density
Merge branch 'master' into features
Merge branch 'master' into features

Conflicts:
	lib_graphd/inc/GraphProperties.h
Added features and working on gtests for them
Added features: edge density, average degree, and degree distribution.
Also added gtests for these. Still need to comment the functions.
Added documentation to the features, ran the GraphPropertiesTest through uncrustify
Changes in feature names now reflected in the gtests
Merging in changes from Jonathan
Make bin dir for tests if it doesn't exist;  fix makefile to rebuild if libgraphd.a changes
adding shortest_path feature
merging upstream/master
fixing spacings