Define, document, validate and test validation of the format of mod.json files.
The mod "name" may only consist of alphanumeric characters, underscore and dash, because it should be used for mod dependency checks.
Drop two special characters from the "version" property.
Differential Revision: https://code.wildfiregames.com/D1093
Res #4427, rP20552
Reviewed By: Itms