Add ability to read from MATPOWER data files

[pelesh]

A significant (though not too time-consuming) task for this project is to add the ability to read from MATPOWER data files.

@rcrutherford, you wrote some file I/O utilities for the ExaGO project, how long do you think it would take you to add this capability? It would likely be only a couple of functions for parsing different options from a matpower file. Please feel free to suggest a deadline and don't be afraid to speak up if you don't feel you have adequate time.

See these docs for reference.

Complete following tasks:

• Staring from function setLookupTable in FileIO.hpp implement prototype for Matpower parser class. The method to read from Matpower netfile should be based on setLookupTable.
  • Use the same approach for reading Matpower netfile. Read line by line and then use string stream to parse each line.
  • For the first cut, I suggest make table as vector of vector of strings.
  • Verify what was read by method based on printLookupTable function.
  • Add feature to skip comments when reading the netfile.
• Parameters for each component should be read into a std::map with key being string describing parameter and value being parameter value.
• Group maps in separate vectors based on the component type. E.g. separate vector for bus maps, branch maps, load maps, etc.

[pelesh]

CC @cameronrutherford @ashermancinelli

[ashermancinelli]

Could you update the repository to reflect the gitlab development? I think this functionality is already present.