fix minor bugs (when compiling) and add callback for custom font

What's Changed

• Bugfix/run 2019 by @psydack in #12
• Feature/use unityengine vectors by @psydack in #11
• Feature/set camera by @psydack in #22
• add font initialize callback by @ousttrue in #24
• fix: #25 use packageRequirements suggestion by @psydack in #26
• Feature/add font init param by @psydack in #27

New Contributors

• @ousttrue made their first contribution in #24

Full Changelog: v4.0.0...v4.1.0