Updated filemanager to use dynamically allocated strings

converted filename to dynamically allocated string
created cstr_helper

src/util/cstr_helper.c

@@ -0,0 +1,22 @@
+
+#include <stdlib.h>
+#include <string.h>
+
+
+int copy_cstr(const char *source, char **destination, size_t *size)
+// Determines length, allocates memory, and returns a null terminated copy
+// Be Aware: caller is responsible for freeing memory
+{
+    size_t len;
+
+    len = strlen(source);
+    *destination = (char *) calloc(len + 1, sizeof(char));
+
+    if (*destination == NULL)
+        return -1;
+    else {
+        strncpy(*destination, source, len);
+        *size = len + 1;
+    }
+    return 0;
+}