Add vim binding to toggle spell check.
Fix auto-reloading of vimrc.

This should work whether editing ~/.vimrc or ~/.dotfiles/vimrc.
Disable vim swap files.
Remove ,h and ,v vim mappings.
Don't hard-code leader key in vimrc.
Add vim binding to toggle paste mode.
Add vim bindings to paste and fix indentation.
Extract vim bindings to a separate file.
Extract vim functions to a separate file.