Avoid name conflicts between Util and Windows function

GetWindow and SwapBuffers are function of Windows.h and using the same
name causes a compile error.

This commit also changes Util's GetProcTableAndDevice to CreateNXTDevice
because we might need to call NXT procs when creating the C++ device.

examples/HelloTriangle.cpp

@@ -14,7 +14,6 @@
 
 #include "Utils.h"
 
-#include <unistd.h>
 #include <vector>
 
 nxt::Device device;
@@ -95,9 +94,7 @@ void initTextures() {
 }
 
 void init() {
-    nxtProcTable procs;
-    GetProcTableAndDevice(&procs, &device);
-    nxtSetProcs(&procs);
+    device = CreateCppNXTDevice();
 
     queue = device.CreateQueueBuilder().GetResult();
 
@@ -173,7 +170,7 @@ void frame() {
         .GetResult();
 
     queue.Submit(1, &commands);
-    SwapBuffers();
+    DoSwapBuffers();
 }
 
 int main(int argc, const char* argv[]) {
@@ -184,7 +181,7 @@ int main(int argc, const char* argv[]) {
 
     while (!ShouldQuit()) {
         frame();
-        usleep(16000);
+        USleep(16000);
     }
 
     // TODO release stuff