Allow binary files to be uploaded

[presto8]

Rewrite code to pass the length of the data and not use NULL termination. This allows binary files to be supported.

[divinity76]

~~any reason this hasn't been merged?~~ edit: last commit was 2018/4 years ago, i guess this project is abandoned? :(

this is shitty imo

hans@DESKTOP-2LHJILI:~$ printf "\x00\x00\x00" > file
hans@DESKTOP-2LHJILI:~$ cat file | nc termbin.com 9999
https://termbin.com/83ms
hans@DESKTOP-2LHJILI:~$ curl 'https://termbin.com/83ms' -s | wc -c
0
hans@DESKTOP-2LHJILI:~$ cat file | wc -c
3