[scheduling] Add cost model classes (mostly stubs for now).
[misc] Add equivalence class implementation.
[misc] Hack eequivalence classes so that they work with scheduler hacks (to be reviewed!)
Merge branch 'master' of github.com:ms705/firmament
Merge branch 'master' of https://github.com/ms705/firmament

Conflicts:
	src/scheduling/flow_graph.cc
Porting firmament typeof to C++11 auto.