[Bug]: Economy date starts in period 1920 instead of 1.

[James103]

Version of OpenTTD

jgrpp-0.58.0 on Windows 10, 64-bit

Expected result

Economy date should start in period 1, like in vanilla OpenTTD.

Actual result

Economy date starts in period 1920, consistent with TTD's earliest possible year.

Steps to reproduce

Set Timekeeping units to Wallclock, start a new game, then run getfulldate. Notice Economy Date starts in 1920-01-01.

[JGRennison]

I changed this (and various other timekeeping-related) things on purpose. I don't have to match vanilla on everything.