Merge pull request #13 from gustafa/malte

Fixing Pion issue, now building with Clang and c++11 support.
[scheduling] [engine] Parametrise debug directory and clean up some code.
[scheduling] Groundwork for dynamic flow graph update.
Merge branch 'master' of github.com:ms705/firmament
[scheduling] Fix regression introduced: flow scheduler fails to call into superclass RegisterResource method and thus does not create an executor.
[scheduling] Fix scheduler paths; Flowlessly now supported.
[engine] Add cost qualifiers to places where they make sense.
[scheduling] Untested work on updating the flow graph on resource registration.
[scheduling] Fix deadlock. Whoops. (We may need to move to a recursive_mutex here.)
[scheduling] Fix initialization bugs for flow graph update functionality.
[scripts] Fix syntax error in plot script (seems to no longer work with latest versions of graphviz).
[engine] Correctly set parent and child relationships for nested coordinator registrations and root of topology tree.
[scheduling] [engine] Fix major issue that led to nested coordinators' resources not being included in the flow scheduler's flow graph. This required a bit of a re-write of some logic; this version works, but may be buggy.
[scheduling] Remove redundant output from DIMACS export.