v0.1.0-beta: Color fixes and Estilo deprecation

Added ⭐️

• dev branch for unstable changes! Woohoo! 🚀
  • Use Plug 'pineapplegiant/spaceduck', { 'branch': 'dev' }
• Add additional syntax highlighting for JavaScript
  • Arrow functions ➡️
  • Object braces and JSX template expressions
  • Destructuring braces
• Highlight variables for colors (e.g., hi SpaceduckRed guifg=#e33400): this should help speed up development for changing colors and preparing the stage for a potential light theme.

Changed 👍

• Change comment color to DarkPurple (temporarily) before finding its own unique color
• Change cyan (string) color to be brighter!
• Better color highlights for CursorLine and Visual

Fixed ✅

• Fix Airline tab bar #25 and status line colors

Deprecated ❌

• Estilo ☠️