Add initial implementation of types and values.

src/value.c

@@ -0,0 +1,15 @@
+#include "value.h"
+
+void libab_value_init(libab_value* value, void* data, libab_ref* type) {
+    value->data = data;
+    libab_ref_copy(type, &value->type);
+}
+
+void libab_value_free(libab_value* value) {
+    void (*free_function)(void*);
+    libab_type* value_type;
+    libab_ref_free(&value->type);
+    value_type = libab_ref_get(&value->type);
+    free_function = value_type->base->free_function;
+    if(free_function) free_function(value->data);
+}