Add Homebrew Cask distribution

[demigodmode]

Description

Enable users to install ClipKit via Homebrew:

brew tap demigodmode/clipkit
brew install --cask clipkit

Implementation

1. Create homebrew-clipkit repo with Cask formula
2. Formula points to GitHub Releases download URL
3. Update on each release

Cost

Free - Homebrew is open source

Future

Once ClipKit gains traction, submit to official homebrew/homebrew-cask for:

brew install --cask clipkit