A binary mode only TFTP server implemented with NodeJS.

How to run:
node run_server.js

TODO: 
* Path sanitizing or whitelisting.
* mkdir -p or similar for subdirectories.
* Temporary filenames for writes, and mv if transfer finishes correctly.
* Use a single timeout for a session, rather than multiple.
* Support for RFC2347, RFC2348 and RFC2349.
* Flow control. Prefer a stable memory picture over fast transfers.