create custom heads without username field

[crashdemons]

reference #30 and meiskam/PlayerHeads#18 subissue

this will cause old heads to not stack with new ones though.

[foxfirecodes]

thanks for contributing this! I actually just committed 0a699ae which addresses this. additionally, it looks like your IDE changed formatting on things which garbled the diff :(

if the changes in the aforementioned commit look good and do all that this PR did, I think it's safe to just close this PR. please let me know if I missed out any changes that you did, it's a bit hard to tell with the formatting changes :)

[crashdemons]

It looks like you got the important parts. the only thing different I did was I made a seperate constructor for the without-name version to leave you more options/preference for the future.

Since I'm in Windows, either git or my IDE change newlines and spaces around. It's different for everyone.
If you're using the github diff, you can add ?w=1 to the page address to only show non-whitespace changes.

I'll close the PR. Thanks!

[foxfirecodes]

gotcha, i don't intend to set usernames at least for now so I should be fine without it.

just a tip, if you set core.autocrlf to true you shouldn't have any problems with git doing this to your line-endings :)
reference: https://git-scm.com/book/en/v2/Customizing-Git-Git-Configuration
git config --global core.autocrlf true

thanks again for contributing this and I tested it out locally, looks like it's running perfectly!