[ruamoko] Clean up Entity a little

Hide own, and add some class spawn methods.

ruamoko/include/Entity.h

@@ -34,10 +34,12 @@
 
 @interface Entity: Object
 {
+	int         own;
 @public
-	entity		ent;
-	int		own;
+	entity      ent;
 }
++(Entity *) spawn;
++(Entity *) withEntity: (entity) e;
 
 - (id) init;
 - (id) initWithEntity: (entity) e;

ruamoko/lib/Entity.r

@@ -15,21 +15,20 @@ int PR_SetField (entity ent, string field, string value) = #0;
 
 @implementation Entity
 
-- (void) own
-{
-	own = 1;
-}
-
 - (id) init
 {
-	self = [self initWithEntity: spawn ()];
-	[self own];
+	if (!(self = [self initWithEntity: spawn ()])) {
+		return nil;
+	}
+	own = 1;
 	return self;
 }
 
 - (id) initWithEntity: (entity)e
 {
-	self = [super init];
+	if (!(self = [super init])) {
+		return nil;
+	}
 	ent = e;
 	ent.@this = self;
 	return self;
@@ -41,6 +40,21 @@ int PR_SetField (entity ent, string field, string value) = #0;
 	return self;
 }
 
++(Entity *) spawn
+{
+	return [[[self alloc] init] autorelease];
+}
+
++(Entity *) withEntity: (entity) e
+{
+	return [[[self alloc] initWithEntity: e] autorelease];
+}
+
++(Entity *) withEntity: (entity) e fromPlist: (plitem_t *) dict
+{
+	return [[[self alloc] initWithEntity: e fromPlist: dict] autorelease];
+}
+
 - (void) dealloc
 {
 	if (own && ent)
@@ -95,7 +109,7 @@ int PR_SetField (entity ent, string field, string value) = #0;
 		}
 	}
 	if (ent)
-		[e own];
+		e.own = 1;
 	return e;
 }