Requirement = function (id, name, version, installed) {
    this.id = id;
    this.name = name;
    this.installed = installed || false;
    this.metadata = {
        version
    };
}
Object thar represents one of requirements for current platform.
@param {String} id         The unique identifier for this requirements.
@param {String} name       The name of requirements. Human-readable field.
@param {String} version    The version of requirement installed. In some cases could be an array of strings
                           (for example, check_android_target returns an array of android targets installed)
@param {Boolean} installed Indicates whether the requirement is installed or not