Add engine core module

The core module will connect all other modules. Currently, it can only
display a message saying "The build-system is working!".

.gitignore

@@ -1,4 +1,4 @@
 
-.private/
+/.private/
-.build/
+/.build/
-voxula
+/voxula

modules/core/inc-c/voxula/internals/core.h

@@ -0,0 +1,18 @@
+
+#ifndef VOXULA_CORE_H
+#define VOXULA_CORE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include <voxula/internals/utility.h>
+
+typedef struct vx_core vx_core_s;
+
+struct vx_core
+{
+    vx_uuid_table_s *uuid_table;
+};
+
+#endif // VOXULA_CORE_H

modules/core/includes.txt

@@ -0,0 +1,6 @@
+{module}/inc-c
+{module-folder}/assets/inc-c
+{module-folder}/ecs/inc-c
+{module-folder}/renderer/inc-c
+{module-folder}/utility/inc-c
+{module-folder}/window/inc-c

modules/core/src-c/main.c

@@ -0,0 +1,7 @@
+#include <voxula/internals/core.h>
+
+int main(int argc, char **argv)
+{
+    puts("The build-system is working!");
+    return -1;
+}