tkd does not build anymore after 2.096

[russhy]

Recent version for nullable removed implicit conversion, you must 
call .get now.. wich is a pain to update


i suggest using a previous version of ``struct Nullable`` 
https://github.com/dlang/phobos/blob/v2.096.1/std/typecons.d

create a nullable.d file in tkd project, and replace the imports 
to that module

that'll solve this issue

but that wouldn't solve the fact that the 
https://code.dlang.org/packages/tkd package won't build

we need to contact the maintainers and suggest to update the 
library


another solution would be to revert the nullable change

that sounds like an unnecessary change that breaks lot of 
code/packages..