Feat: Add token counting

[Angelchev]

Closes: #41

Overview

• [x] Add command to count tokens from a visual selection.
• [x] Add python script to count tokens with OpenAI's tiktoken.
• [x] Add utils.vim to launch python scripts more easily.
• [x] Add automatic venv setup for Neovim with lazy.nvim package manager via build.lua.
  • [x] Create a python virtual environment automatically for Linux or Windows (Untested).
  • [x] Install dependencies from requirements.txt automatically.
• [x] Add Neovim animated notification integration with nvim-notify.

Todo

• [ ] Add python test for new script
• [ ] Check for tiktoken dependency in Python script, and throw error if not present.
• [ ] Investigate automatically setting up python venv and installing requirements for vim 8.
• [ ] Update README.md to document optionally setting up python venv.
• Update vimdocs:
  • [ ] New command and availability dependant on tiktoken
  • [ ] Integration of nvim-notify

Testing

• Test automatic setup for Neovim with lazy.nvim.
  • [x] Linux
  • [ ] Mac OSX
  • [ ] Windows

Screenshots

Neovim Animated Notifications via nvim-notify

Automatic venv setup for Neovim with lazy.nvim