Beep-Boops on Code Lock Fixes

[saccharineChampion]

https://github.com/goonstation/goonstation-2020/pull/51

Without the patch, the manner in which the determination of beeps and boops when hacking a safe causes it to give erroneous results. This patch changes the system to use a variable like a set of four flags instead of the old system which removed letters from a copy of the lock code, which caused aforementioned oddity. Peace and love.

DMI file links:

https://drive.google.com/open?id=1wMeJeh...iI5Jbt1Lm9

https://drive.google.com/open?id=1g-RY2W...6Ln8G1GTsj

[phyvo]

I encountered this bug half a year ago when I was mapping every possible combination of beep/boops in game, trying to figure out how safecracking worked. I couldn't find any simple rules that made sense of *everything* in my resulting spreadsheet. I shrugged my shoulders, and moved on. It's nice to see a fix so that I don't feel quite as dumb as I thought I was.

[pali6]

Merged.