Add cabal_sandbox_info function

Reports whether the current working directory is within a
sandbox. Useful to check before installing Cabal packages into the
global registry.
Fix URL to gi (gitignore) function

Previous URL doesn't seem to work because the host requires a www
prefix.
Update gitignore.plugin.zsh

Fix URL to gi (gitignore) function in _gitignireio_get_command_list function
Adieu l'ami.

 @jimweirich -- You will be missed.
..a fundamental piece of matter.
vi mode
remove unused aliases