Odin game code hotloading host.

Based on this article by Karl Zylinski: https://zylinski.se/posts/hot-reload-gameplay-code/

Project/
├─ src/
│  ├─ game.odin
├─ build/
│  ├─ boxxer.exe
│  ├─ game.dll

cd build
boxxer.exe -src:C:\code\Project\src -pkg:src -dll:game

• -src: The code directory that efsw should watch for file saves. Saving files in your game package directory (including subfolders) will trigger a hotload automatically.
• -pkg: The package folder name of your odin code. In the example above it would be src with how I've laid out my project. It would be whatever the root folder for your game code is. Needed for telling Odin how to compile your game package.
• -dll: The name of your game's output dll. This is what boxxer will tell the Odin compiler what to name your game package dll.