Implement features for font name strings
Created by: lo48576
I want to get font name with https://github.com/dylanede/rusttype, but it doesn't provide such feature. I wrote this PR to help implement rusttype feature to get font name (or any useful information to identify fonts).
Types like PlatformEncodingLanguageID
or FontNameIter
are not implemented in original stb_truetype, but they may be useful and should be in this crate.