Add gencost to Case format
Created by: espenol
Added gencost to Case so that it is loaded and stored there, added gencost for the test (power) systems in the repository and added a simple test to verify that a value in gencost is loaded correctly.
Scheduled maintenance will be performed on March 19th between 19:00-23:00. There will also be unstability with object storage on March 17th between 18:00-20:00
Created by: espenol
Added gencost to Case so that it is loaded and stored there, added gencost for the test (power) systems in the repository and added a simple test to verify that a value in gencost is loaded correctly.