Header allowed characters

As talked about in this conversation: !48 (comment 1036323131) We don't currently know what characters DF accepts in the header files. Does it accepts all Unicode characters, Or just a few (maybe just CP437 characters).

Are headers like accepted?:

• valid_header_𒀧ꨣ⠹𖠄⻚ق_Still_valid (lot of other Unicode characters)
• valid part of the header (spaces are allowed too, even tabs)

This might require some testing in game.

Get started:

• Create a simple mod, you can use existing mod files (for example), or use an example file.
• Make sure the mode works first. (check the object is loaded correctly) https://dwarffortresswiki.org/index.php/DF2014:Modding#Basics_of_DF_modding
• Apply some changes to the file, save it and reload the game and see if it still works.
• Report the findings below. (incomplete tests are still welcome)