Added memory arena

Fixed frames in flight validation error in vulkan
Added some utility macros
Added function decorator macros
Added some consolidation headers/code include files

code/os/core.h

@@ -0,0 +1,14 @@
+#if !defined(LD_OS_CORE_H_)
+#define LD_OS_CORE_H_
+
+// Virtual memory
+
+function U64 VM_PageSize();
+function U64 VM_AllocationGranularity();
+
+function void *VM_Reserve(U64 size);
+function B32   VM_Commit(void *base, U64 size);
+function void  VM_Decommit(void *base, U64 size);
+function void  VM_Release(void *base, U64 size);
+
+#endif  // LD_OS_CORE_H_