Move LOLE calculation to the Merit gem
Capacity attributes are required for the LOLE calculation
flatten_compact should cast Enumerables to Array
Set up a Merit Order for the present graph

The present graph merit order IS NOT run, however load and curve data is
set so that LOLE and peak demand queries can be used.

Ref quintel/merit#126
Ref quintel/etsource#895
Use LoadProfile cache in development
Fix some broken tests which are older than our sun
Merge pull request #726 from quintel/lole

Move LOLE calculation to the Merit gem