v0.1.0 prep - Refactor File/Parser handling and add external call highlighting

[tintinweb]

• refactored parser and turned it into its own library
  • tries to resolve external calls
• added external call highlighting and an extcall view in the cockpit

fixes #8

editor - gutter icons for external calls (⚠️)

cockpit - list external calls for current contract

hover - resolve inherited names (clickable declarations)

[GNSPS]

🔥

[tintinweb]

whoop, let's get this into master 🥳