Merge pull request #116 from honkdamonk/master

Optimization for reduce operations on fields
dijkstra.gm
dijkstra bug fix
Added modifed versions of the shortest path apps (based on original G-M one and Dijkstra) working with adjacency list file containing edge costs of type double.
New versions of the shortes path programs will now be built by default.
Merge branch 'master' of https://github.com/stanford-ppl/Green-Marl