Doesn't save binaries uploaded if the 'data-dir' doesn't exist.

[muman613]

Issue

When a user uploads a binary file the demo app should save the binary to a file in the 'data-dir' directory. If this directory doesn't exist the application prints a log message about it failing to write the file. The demo should create the data-dir if it doesn't already exist.

[muman613]

I think this issue may have been resolved.