GSvit documentation

Originally, only a *command line solver GSvit* was released. Benefits of a command line tool are namely seen when you want to do some scripting, or you are using remote access to some high performance computing system.

To assist with setting up the parameter files, later a simple *parameter file viewer XSvit* was added, which also has some basic functionality in running the calculation (calling GSvit) and visualising some of the results. It still operates only with the text parameter files used in GSvit so you can edit your parameter files in any other text editor as well.