Don't double-escape shell commands

[cpeel]

Using escapeshellarg() to escape user inputs being passed as args is all that is necessary before running a command. escapeshellcmd() can double encode unmatched double- and single-quotes when used with escapeshellarg().

https://gist.github.com/Zenexer/40d02da5e07f151adeaeeaa11af9ab36 is an interesting read.

Testable at https://www.pgdp.org/~cpeel/ppwb

[cpeel]

TEST and PROD have both been updated with this code.