made examples/demos for vectors && files && lists | also fixed a bug with the vector and list size and popping, explained in the adjacent comment

examples/list/listdemo.c

@@ -0,0 +1,21 @@
+#include <odweta/list.h>
+#include <stdio.h>
+
+int main() {
+    printf("creating a list using 'listInit()' (returns a list_t*)\n");
+    list_t* l = listInit();
+
+    printf("pushing an integer value into the list\nnote the kind of unusual way of passing the number argument: if you want to pass an expression (e.g. the value '1' or '4*4'), something not stored in a variable, you follow this syntax - &(type){value} (e.g. &(int){1 + 1})\nalso, the type of the variable must be given as the second argument to the function\n->'listPush(list_t*, INT, &(int){123})'\n");
+    listPush(l, INT, &(int){123});
+    listPrint(l);
+
+    printf("popping the last value of the list; in this case, it is an integer, so you type: 'int poppedValue = *((int *)listPop(list_t*))'\n");
+    int poppedValue = *((int *)listPop(l));
+	printf("popped: %d\n", poppedValue);
+    listPrint(l);
+
+    printf("if you are finished working with the list BEFORE the immediate end of the program, run 'listCleanup(list_t*)', otherwise it is not strictly necessary\n");
+    listCleanup(l);
+
+    return 0;
+}