major rework

major rework

- remove unused configs, themes, icons, scripts
- update installer
  - now respect xdg env vars
  - clean out old links from our source tree before reinstall
  - apply default permissions to created dirs
- update vim
  - remove unused plugins
  - move vim dir to xdg config dir (zsh VIMINIT)
  - undo and backup dirs are autocreated and are moved to xdg
  - remove modeline support
  - add editorconfig plugin
- update zsh
  - move zsh dotfiles to xdg config subdir
  - all zsh local dotfiles are now relative to ZDOTDIR
  - xdg env vars are now mostly default
  - better xdg handling in general
  - fixed xdg *_DIRS empty array index
  - redesign tmpdir generation method
  - ~/bin moved to ~/.local/bin per xdg
  - better broken TERM handling
  - ~/.gnupg moved to ~/.config/gnupg
  - gpgagent refresh is more usable now
  - preferred list of EDITORs, PAGERs, and TERMINALs
  - ~/.zcompdump moved to ~/.cache/zsh/.zcompdump
  - prompt_arrows_preexec removed because it's annoying
- python
  - ~/.pythonrc moved to ~/.config/pythonrc (zshrc PYTHONSTARTUP)