add extensions include

include/sp/extensions/Extensions.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#if __has_include(<sp/extensions/Compress.h>)
+	#include <sp/extensions/Compress.h>
+#endif

test/test_packets.cpp

@@ -3,6 +3,8 @@
 #include <examples/PacketExample.h>
 #include <memory>
 
+#include <sp/extensions/Extensions.h>
+
 class KeepAliveHandler : public sp::PacketHandler {
 	void Handle(const KeepAlivePacket& packet) {
 		std::cout << "KeepAlive handled !\n";