Step size is stored as double (like fmi standard). Guid renamed

ProtoDefinitions/SimulationSettings.proto

@@ -14,7 +14,7 @@ message ProtoChannelLink {
 // Instance of a fmu model. In the frontend a DataSource represents a FmuInstance.
 message ProtoFmuInstance {
     string instance_name = 1;   // Name of one concrete instance (from fmi2Instantiate)
-    string model_guid = 2;  // The guid of the model (from modelDescription.xml)
+    string guid = 2;  // The guid of the model (from modelDescription.xml)
     repeated ProtoChannel channels = 3;
 }
 
@@ -29,5 +29,5 @@ message ProtoSimulationSettings {
     repeated ProtoChannelLink channel_links = 1;
     repeated ProtoFmuInstance fmu_instances = 2;
     ProtoRemoteSettings remote_settings = 3;
-    int64 step_size_nanoseconds = 4;   // High precision, max ~ 100000 days ;)
+    double step_size = 4;   // In seconds
 }