Split fs.c file

+ Misc changes to code in io.c

source/tegraexplorer/io.h

@@ -0,0 +1,10 @@
+#pragma once
+
+bool checkfile(char* path);
+void viewbytes(char *path);
+int copy(const char *locin, const char *locout, bool print, bool canCancel);
+u64 getfilesize(char *path);
+int getfolderentryamount(const char *path);
+void makestring(char *in, char **out);
+int del_recursive(char *path);
+int copy_recursive(char *path, char *dstpath);