Rename 'Standard Gaming Platform' to 'sgp' (#246)

* rename 'Standard Gaming Platform' to 'sgp'

* Adapt CMakeLists.txt files to renamed SGP directory

* Lowercase it

sgp/TopicOps.h

@@ -0,0 +1,25 @@
+#ifndef _TopicOps_h
+#define _TopicOps_h
+
+// debug levels
+
+#define DBG_LEVEL_0		0	// for registering and unregistering topics only
+#define DBG_LEVEL_1		1	// for basic stuff
+#define DBG_LEVEL_2		2	// for ordinary, I usually want to see them, messages
+#define DBG_LEVEL_3		3	// nitty gritty detail
+
+// from client
+
+#define TOPIC_REGISTER	0
+#define TOPIC_UNREGISTER	1
+#define TOPIC_MESSAGE	 2
+#define CLIENT_REGISTER	3
+#define CLIENT_SHUTDOWN	4
+
+// from server
+
+#define SYSTEM_SHUTDOWN	0
+#define MODULE_RESET		1
+#define SET_DEBUG_LEVEL	2
+
+#endif