windows: Fix various warnings

Categories include:
 ASSERT_TRUE(int) changed to ASSERT_TRUE(0 != int)
 Change uint32_t to DeviceSize
 Stop adding with bools
 Add some explicit casting
 Remove unreferenced variables
 Add 'f' suffix to float literals

Conflicts:
	tests/vkrenderframework.cpp
diff --git a/layers/screenshot.cpp b/layers/screenshot.cpp
index 1b8197e..7f8ce4a 100644
--- a/layers/screenshot.cpp
+++ b/layers/screenshot.cpp
@@ -271,7 +271,7 @@
 
 static void createDeviceRegisterExtensions(const VkDeviceCreateInfo* pCreateInfo, VkDevice device)
 {
-    uint32_t i, ext_idx;
+    uint32_t i;
     VkLayerDispatchTable *pDisp  = get_dispatch_table(screenshot_device_table_map, device);
     deviceExtMap[pDisp].wsi_enabled = false;
     for (i = 0; i < pCreateInfo->extensionCount; i++) {